<PAGE>   1
                                                                   EXHIBIT 10.24



                                  OFFICE LEASE




                              NAPERVILLE CORPORATE
                               CENTER SUBDIVISION



                                    BETWEEN



                             AMERICAN NATIONAL BANK
                          AND TRUST COMPANY OF CHICAGO
                                TRUST NO. 43194

                                  as Landlord





                                      AND



                                 SPYGLASS, INC.

                                   as Tenant

                              1240 East Diehl Road
                              Naperville, Illinois


<PAGE>   2

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
NO.              DESCRIPTION                                                            PAGE
---              -----------                                                          -------
<S>      <C>                                                                          <C>     

1.       BASIC LEASE PROVISIONS AND IDENTIFICATION OF EXHIBITS
         1.01 BASIC LEASE PROVISIONS                                                     1
         1.02 IDENTIFICATION OF EXHIBITS                                                 2

2.       PREMISES AND TERM                                                               2
         2.01 LEASE OF PREMISES                                                          2
         2.02 TERM OF LEASE                                                              2
         2.03 INSTALLATION OF EQUIPMENT BY TENANT                                        2
         2.04 AGREEMENT STATING COMMENCEMENT AND EXPIRATION
                DATES OF LEASE                                                           2

3.        RENT                                                                           2

4.        SECURITY DEPOSIT                                                               3

5.        SERVICES                                                                       3
          5.01 LANDLORD'S GENERAL SERVICES                                               3
          5.02 ADDITIONAL AND AFTER-HOUR SERVICES                                        3
          5.03 TENANT'S UTILITIES                                                        4
          5.04 DELAYS IN FURNISHING SERVICES                                             4
                                     
6.        POSSESSION, USE AND ENJOYMENT                                                  4
          6.01 POSSESSION AND USE OF PREMISES                                            4
          6.02 QUIET ENJOYMENT                                                           5

7.        CONDITION OF PREMISES                                                          5

B.        ASSIGNMENT AND SUBLETTING                                                      5
          8.01 ASSIGNMENT AND SUBLETTING                                                 5
          8.02 RECAPTURE                                                                 6

9.        MAINTENANCE AND REPAIR                                                         6
          9.01 LANDLORD'S MAINTENANCE AND REPAIR                                         6
          9.02 TENANT'S MAINTENANCE AND REPAIR                                           7

10.      ALTERATIONS AND IMPROVEMENTS SUBSEQUENT TO INITIAL
         OCCUPANCY                                                                       7
         10.01 TENANT'S ALTERATIONS SUBSEQUENT TO INITIAL                        
                OCCUPANCY                                                                7
         10.02 LIENS                                                                     8

11.      WAIVER OF CLAIMS AND INDEMNITY                                                  8
         11.01 WAIVER                                                                    8  
         11.02 INDEMNIFICATION                                                           8

12.      LANDLORD'S REMEDIES                                                             9
         12.01 EVENTS OF DEFAULT                                                         9
         12.02 LANDLORD'S REMEDIES                                                       9
         12.03 TRUSTEE IN BANKRUPTCY                                                     10
         12.04 ATTORNEYS' FEES                                                 
                                                                                         10
                                                                
13.      SURRENDER OF PREMISES                                                           10

14.      HOLDING OVER                                                                    10

15.      DAMAGE BY FIRE OR OTHER CASUALTY                                                11
         15.01 SUBSTANTIAL UNTENANTABILITY                                               11
         15.02 INSUBSTANTIAL UNTENANTABILITY                                             11
         15.03 RENT ABATEMENT                                                            11
         15.04 DEFINITIONS                                                               11

16.      EMINENT DOMAIN . . . . . . . . . . . . . . . . . . .                            12
         16.01 SUBSTANTIAL TAKING . . . . . . . . . . . . .                              12
                                                                                                        
</TABLE>



<PAGE>   3

<TABLE>
<S>      <C>                                                                          <C>      
         16.02 INSUBSTANTIAL TAKING . . . . . . . . . . . . .                            12
         16.03 COMPENSATION . . . . . . . . . . . . . . . . .                            12

17.      TENANT'S INSURANCE .   . . . . . . . . . . . . . . .                            12

18.      RULES AND REGULATIONS  . . . . . . . . . . . . . . . . .  I                     13

19.      LANDLORD'S RIGHTS  . . . . . . . . . . . . . . . . . . .                        14

20.      ESTOPPEL CERTIFICATE . . . . . . . . . . . . . . . . . .                        15

21.      INTENTIONALLY DELETED  . . . . . . . . . . . . . . . . .                        15

22.      ADJUSTMENTS TO MONTHLY BASE RENT . . . . . . . . . . . .                        16
         22.01  DEFINITIONS . . . . . . . . . . . . . . . . . . .                        16
         22.02  ADJUSTMENTS TO MONTHLY BASE RENT. . . . . . . . .                        17
         22.03  PROJECTIONS . . . . . . . . . . . . . . . . .                            17
         22.04  READJUSTMENTS . . . . . . . . . . . . . . . .                            17
         22.05  BOOKS AND RECORDS . . . . . . . . . . . . . .                            18
         22.06  NO DECREASES IN MONTHLY BASE RENT                                        18
         22.07  PARTIAL OCCUPANCY FOR OPERATING EXPENSES                                 18

23.      REAL ESTATE BROKERS                                                             18

24.      SUBORDINATION AND ATTORNMENT                                                    18
         24.01 SUBORDINATION                                                             18
         24.02 ATTORNMENT                                                                19

25.      NOTICES                                                                         19

26.      MISCELLANEOUS                                                                   19
         26.01  LATE CHARGES                                                             19
         26.02  ENTIRE AGREEMENT                                                         19
         26.03  NO OPTION                                                                20
         26.04  ACCORD AND SATISFACTION                                                  20
         26.05  LIMITATION OF LIABILITY                                                  20
         26.06  BINDING EFFECT                                                           20
         26.07  FORCE MAJEURE                                                            20
         26.08  CAPTIONS                                                                 21
         26.09  APPLICABLE LAW                                                           21
         26.10  TIME                                                                     21

         26.11    LANDLORD'S RIGHT TO PERFORM TENANT'S DUTIES                            21
         26.12    TENANT'S REMEDIES                                                      21
         26.13    RIDERS                                                                 21
         26.14    CONSENT                                                                21

27.      PARKING                                                                         21
                                                                                                
</TABLE>



<PAGE>   4


                                  OFFICE LEASE

                                       1.

             BASIC LEASE PROVISIONS AND IDENTIFICATION OF EXHIBITS

1.01     BASIC LEASE PROVISIONS

A.       BUILDING & ADDRESS:

         1240 East Diehl Road Building
         1240 East Diehl Road
         Naperville, Illinois 60563

B.       LANDLORD & ADDRESS:

         American National Bank and Trust
         Company of Chicago, not individually
         but solely as Trustee under a Trust
         Agreement dated June 12, 1978 and
         known as Trust No. 43194
         c/o Bellemead Management Co., Inc.
         280 Corporate Center
         Four Becker Farm Road
         Roseland, New Jersey 07068

C.       TENANT & CURRENT ADDRESS:

         Spyglass, Inc.
         1240 East Diehl Road
         Naperville, Illinois 60563


D.       DATE OF LEASE: May 28,1997

E.       LEASE TERM: Two (2) years

F.       COMMENCEMENT DATE OF TERM: February 1, 1998

G.       EXPIRATION DATE OF TERM: January 31, 2000

H.       MONTHLY BASE RENT: *

I.       RENTABLE SQUARE FEET OF THE PREMISES
         UPON WHICH MONTHLY BASE RENT AND ADJUSTED
         MONTHLY BASE RENT IS CALCULATED: 27,864 FLOOR: 4th

J.       SECURITY DEPOSIT: $46,285.66

K.       BROKER: CB Commercial Real Estate Group, Inc. and Grubb & Ellis
         Company

L.       RENTABLE SQUARE FEET OF THE BUILDING: 139,184 square feet

M.       TENANT'S PROPORTIONATE SHARE: 20.00%


                                              Monthly   Annual Rate of Base Rent
            *Period                         Base Rent   Per Rentable Square Foot
       2/l/98 - 1/31/99                    $46,285.66                    $19.95
       2/l/99 - 1/31/00                     47,445.70                     20.45

                                     Page 1



<PAGE>   5


1.02     IDENTIFICATION OF EXHIBITS

The exhibits set forth below and attached to this Lease are incorporated in
this Lease by this reference and are hereby made a part of this Lease:

                                EXHIBIT A -          Plan of Premises
                                EXHIBIT B -          Intentionally Deleted
                                EXHIBIT C -          Cleaning Specifications


                                      2.

                                PREMISES AND TERM

2.01      LEASE OF PREMISES

Landlord leases to Tenant and Tenant leases from Landlord the premises (the
"Premises") outlined in red on Exhibit A, which are contained in the office
building described in 1.01A (the "Building"), upon the following terms and
conditions.

2.02      TERM OF LEASE

The term of this Lease (the "Term") shall commence on the date (the
"Commencement Date") which is set forth in 1.61 F of this Lease.  The Term
shall expire on the date (the "Expiration Date") specified in Paragraph 1.01G
of this Lease unless sooner terminated as otherwise provided in this Lease.

2.03      INSTALLATION OF EQUIPMENT BY TENANT

         If prior to the Commencement Date, Tenant shall enter the Premises to
make any installation of Tenant's equipment, fixtures or furnishings, Landlord
shall have no liability or obligation for the care or preservation of Tenant's
property.

2.04      AGREEMENT STATING COMMENCEMENT AND EXPIRATION DATES OF LEASE

Upon request by Landlord or Tenant after the Commencement Date, Landlord and
Tenant will sign and deliver to each other an agreement in form and substance
satisfactory to Landlord setting forth the Commencement Date and the Expiration
Date.
                                       3.

                                      RENT

Tenant agrees to pay to Landlord c/o Bellemead Management Co., Inc., a New
Jersey corporation, 280 Corporate Center, Four Becker Farm Road, Roseland, New
Jersey 07068, or at such other place designated by Landlord, without any prior
notice or demand and without any set-off or deduction whatsoever, base rent at
the initial monthly rate stated in 1.01H ("Monthly Base Rent").  Monthly Base
Rent is subject to adjustment pursuant to Article 22, and as adjusted is called
"Adjusted Monthly Base Rent." Monthly Base Rent and Adjusted Monthly Base Rent
shall be paid monthly in advance on the first day of each month of the Term.
Monthly Base Rent and Adjusted Monthly Base Rent shall be prorated for partial
months within the Term.  All charges, costs and sums required to be paid by
Tenant to Landlord under this Lease, in addition to Monthly Base Rent and
Adjusted Monthly Base Rent, shall be considered additional rent, and Monthly
Base Rent, Adjusted Monthly Base Rent and additional rent shall be collectively
called "Rent".  Tenant's covenant to pay Rent shall be independent of every
other covenant in this Lease.

                                     Page 2


<PAGE>   6


                                       4.

                                SECURITY DEPOSIT

         As security for the performance of its obligations under this Lease
and the Work Agreement, Tenant upon its signing of this Lease shall pay to
Landlord a security deposit (the "Security Deposit") in the amount stated in
1.01J. The Security Deposit may be applied by Landlord to cure any default of
Tenant under this Lease or the Work Agreement, and upon notice by Landlord of
such application, Tenant shall replenish the Security Deposit in full by
promptly paying to Landlord the amount so applied.  Landlord shall not pay any
interest on the Security Deposit.  Within 45 days after the Expiration Date,
Landlord shall return to Tenant the balance, if any, of the Security Deposit.
The Security Deposit shall not be deemed an advance payment of Rent or a
measure of damages for any default by Tenant under this Lease, nor shall it be
a bar or defense to any action which Landlord may at any time commence against
Tenant.


                                       5.

                                    SERVICES

5.01      LANDLORD'S GENERAL SERVICES

Landlord shall provide the following services (subject to the provisions of
this Lease and applicable legal restrictions):

        (1)     heat and air-conditioning in the Premises, Monday through
    Friday, from 8:00 A.M. to 6:00 P.M., Saturday from 8:00 A.M. to 1:00 P.M.,
    Sunday and national holidays excepted, in sufficient amount to maintain an
    average temperature in the Premises between 65 degrees Fahrenheit and 80
    degrees Fahrenheit, provided that the Premises are not occupied by more
    than an average of one person for each 150 square feet of actual floor
    space in the Premises and provided further that no machine or equipment is
    located in the Premises which affects the temperature otherwise maintained
    in the Premises;

        (2)   city water from the regular Building fixtures for drinking,
    lavatory and toilet purposes only;

        (3)   cleaning services in the Premises Monday through Friday,
    excluding Saturdays, Sundays and national holidays (observed),
    substantially in accordance with the cleaning specifications attached
    hereto as Exhibit C; and which services shall be provided by bonded
    cleaning personnel; and

        (4)     passenger elevator service in common with other tenants of the
    Building, 24 hours per day, 7 days per week, subject to applicable laws and
    emergencies.

Notwithstanding the provisions of this Paragraph 5.01, nothing in this
Paragraph 5.01 shall affect or reduce Tenant's obligation to pay any escalation
in Operating Expenses as set forth in 22.02 of this Lease.

5.02      ADDITIONAL AND AFTER-HOUR SERVICES

Landlord shall not be obligated to furnish any services or utilities, other
than those stated in 5.01 above.  If Landlord elects to furnish services or
utilities requested by Tenant in addition to those listed in 5.01 or at times
other than those stated in 5.01, Tenant shall pay to Landlord the charges
specified by Landlord for such services and utilities, within 10 days after
billing by Landlord.  If Tenant fails to make any such payment, Landlord may,
without notice to Tenant and in addition to Landlord's other remedies under
this Lease, discontinue any or all of such additional or after-hour services.
No such discontinuance of any service shall result in any liability of Landlord
to Tenant, or be considered an eviction or a disturbance of Tenant's use of the
Premises, or relieve Tenant from its obligation to pay all Rent when due or
from any other obligation of Tenant under this Lease.

                                     Page 3


<PAGE>   7


5.03     TENANT'S UTILITIES

         Tenant, at Tenant's cost and expense, shall make arrangements directly
with the telephone company for telephone service and the installation of wires
and cables therefor.  Tenant shall pay for all telephone and electric service
used or consumed in the Premises, including without limitation the cost of such
installation of wires and cables for such service.  Any installation of
telephone service in the Premises by Tenant shall be in compliance with the
National Electric Code 300-22.  Landlord, at its option, may purchase
electricity in bulk for the Building, and supply electricity to Tenant for its
use in the Premises.  Tenant's electrical usage shall be measured by an
electronic meter.  In such event, Tenant shall pay to Landlord (or to any
electrical contractor retained by Landlord to provide billing and accounting
services for such electrical service) all charges for electricity used in the
Premises within 10 days after each bill is rendered.  Any such charges billed
by Landlord (or Landlord's electrical contractor) shall not exceed the charges
which Tenant would otherwise be required to pay if Tenant purchased such
electricity directly from the public utility company providing electricity to
the Building.

5.04      DELAYS IN FURNISHING SERVICES

Notwithstanding anything to the contrary set forth in this Lease, Landlord
shall not be liable for damages for any failure to furnish or delay in
furnishing any service or utility described in 5.01 or 5.02 above if such
failure or delay is caused in whole or in part by any one or more of the causes
specified in 26.07 of this Lease.  No such failure or delay caused in whole or
in part by any one or more of the causes specified in 26.07 of this Lease shall
result in any liability of Landlord to Tenant or be deemed to be an eviction or
disturbance of Tenant's use or possession of the Premises, or relieve Tenant
from its obligation to pay all Rent when due or from any other obligation of
Tenant under this Lease.  See Insert on page 4A.


                                       6.

                         POSSESSION, USE AND ENJOYMENT

6.01      POSSESSION AND USE OF PREMISES

Tenant shall be entitled to possession of the Premises upon the date stated in
Section 1.01F. Tenant shall occupy and use the Premises for general office
purposes only.  Tenant shall not occupy or use the Premises or permit the use
or occupancy of the Premises for any purpose or in any manner which:

        (1)     is unlawful or in violation of any applicable legal,
    governmental or quasi-governmental requirement, ordinance or rule
    (including the rules of the Board of Fire Underwriters);

        (2)      may be dangerous to persons or property;

        (3)     may invalidate or increase the amount of premiums for any
    policy of insurance affecting the Building or covering its operation or
    violate the terms thereof and if any additional amounts of insurance
    premiums are payable as a result of Tenant's occupancy or use of the
    Premises, Tenant shall pay to Landlord the additional amounts on demand;

        (4)     may create a nuisance, disturb any other tenant of the Building
    or the occupants of neighboring property or injure the reputation of the
    Building; 

        (5)     will conflict with any exclusive rights granted to any other
    tenant in the Building; or

                                     Page 4



<PAGE>   8


Notwithstanding the foregoing, if as a result of an act or omission of
Landlord (as distinguished from an act or omission of Tenant or the occurrence
of an event of force majeure as defined in Section 26.07 below), electricity,
heating, air conditioning, restroom facilities, or passenger elevator service to
the Premises, as described in Section 5.01 above, is not furnished to the
Premises, and if as a result thereof the Premises, or a "material part" (as
defined below) of the Premises is rendered untenantable or inaccessible for a
period of five (5) consecutive business days, and Tenant does not occupy the
Premises, or such material part thereof which is rendered untenantable or
inaccessible, during such 5-business day period, then as Tenant's sole remedy
for such failure to furnish such service, Adjusted Monthly Base Rent payable for
such portion of the Premises which Tenant does not so occupy shall abate for the
period commencing on the expiration of said five (5) business day period and
expiring on the date such service is restored or Tenant is able to resume
occupancy of the Premises or such material part thereof, as the case may be. As
used herein, the phrase "material part" shall mean an amount in excess of fifty
percent (50%) of the rentable area of the Premises.

                                    Page 4A



<PAGE>   9


(6)                 will violate the provisions of any covenant, condition,
                    restriction, agreement or document which is recorded in the
                    office of the Recorder of DuPage County, Illinois and which
                    affects all or any part of the Building or Lot 3 of the
                    Resubdivision of Lot 3 in the Naperville Corporate Center
                    Subdivision in Naperville, Illinois.

6.02      QUIET ENJOYMENT

So long as Tenant is not in default under this Lease, Tenant shall be entitled
to peaceful and quiet enjoyment of the Premises, subject to (1) the provisions
of this Lease, (ii) any governmental action, and (iii) any cause beyond the
reasonable control of Landlord.

                                       7.

                             CONDITION OF PREMISES
         Tenant shall be conclusively presumed to have accepted the Premises in
the condition existing on the date Tenant first takes possession of the
Premises and to have waived all claims relating to the condition of the
Premises.  No agreement of Landlord to alter, remodel, decorate, clean or
improve the Premises or the Building and no representation or warranty
regarding the condition of the Premises or the Building or regarding any other
matter of any kind or nature has been made by or on behalf of Landlord to
Tenant, except as expressly stated in this Lease.

                                       8.
                           ASSIGNMENT AND SUBLETTING

8.01      ASSIGNMENT AND SUBLETTING

Without the prior written consent of Landlord, Tenant shall not (i) sublease
all or any part of the Premises, or assign, convey, encumber, mortgage, pledge,
hypothecate or otherwise transfer or permit the transfer of the interest of
Tenant in this Lease, in whole or in part, by operation of law or otherwise, or
(ii) permit the use and occupancy of all or any part of the Premises by any
party other than Tenant, its agents, employees, invitees and guests., If Tenant
desires to assign Tenant's interest in this Lease or enter into any sublease of
all or any part of the Premises, Tenant shall, after compliance with Paragraph
8.02 below, deliver written notice of such intent to Landlord, together with
(x) a copy of the proposed assignment or sublease, (y) such current financial
information regarding the proposed subtenant or assignee as is reasonably
necessary for Landlord to determine its creditworthiness, and (z) such
background information regarding the proposed subtenant or assignee as is
reasonably necessary for Landlord to determine its identity, reputation and
type of business, at least 45 days prior to the effective date of the proposed
assignment or commencement date of the term of the proposed sublease. Any
sublease approved by Landlord shall be expressly subject to the terms and
conditions of this Lease, and Tenant, in addition to Tenant's other obligations
under this Lease, shall pay to Landlord on the first  day of each month during
the term of such sublease 50% of the excess of all rent and other consideration
due from the subtenant for such month over that portion of the Adjusted Monthly
Base Rent due under this Lease for said month which is allocable on a square
footage basis to the space sublet,**. In the event of an approved assignment of
this Lease by Tenant, Tenant shall pay to Landlord as and when received by
Tenant, 50% of all sums and other consideration received by Tenant from
Tenant's assignee,**. In the event of any approved sublease or approved
assignment, Tenant shall not be released or discharged from any liability,
whether past, present or future, under this Lease, including any renewal term
of this Lease approved by Landlord. For the purpose of this Paragraph, an
assignment shall be considered to include a change in the majority ownership or
control of Tenant if Tenant is a partnership or a corporation whose shares of
stock are not traded publicly,***. In no event shall (i) any sublease of all or
any part of the Premises be for a term of less than six (6) months, (ii) Tenant
enter into one or more subleases of all or any part of the Premises which
permit more than two subtenants to occupy all or any part of the Premises at
the same time, (iii) the,- net effective annual rent per rentable square foot
(as

                                     Page 5



<PAGE>   10


*Landlord agrees that Landlord's consent to a proposed assignment or sublease
shall not be unreasonably withheld.

**after deduction of the reasonable and appropriate out-of-pocket costs paid by
Tenant in connection with such transfer for build-out (which costs shall be
amortized over the term of the transfer), brokerage commissions and attorneys'
fees.

***but only if the net worth of Tenant after such change of control is less
than the net worth of Tenant immediately prior to such, change in control (and
Tenant shall provide to Landlord upon request current financial statements of
Tenant before and after such change in control).

                                    Page 5A




<PAGE>   11



determined by Landlord) payable by the subtenant under any sublease, taking
into account all rental adjustments and subtenarit concessions (e.g., rental
abatements, improvement allowances, relocation allowances and lease take-over
obligations), be substantially less than prevailing market net effective annual
rent per rentable square foot (as determined Landlord) then in effect for
comparable space in the Building, taking into account the prevailing market
rental adjustments and tenant concessions for such comparable space, or (iv)
any assignee or subtenant be in existing tenant of the Naperville Corporate
Center Subdivision, or an affiliate of such existing tenant.  See Insert on
Page 6A.
        
8.02 RECAPTURE

         If Tenant desires to assign this Lease (other than to an affiliate) or
to sublease all or any part of the Premises (other than to an affiliate),
Tenant shall give Landlord written notice of such intent ("Tenant's Notice")
prior to Tenant entering into such assignment or sublease, which Tenant's
Notice shall identify the space to be subleased and the proposed commencement
date of the term of such sublease, or the proposed effective date of such
assignment, as the case may be.  Landlord shall thereupon have the option to
exclude from the Premises covered by this Lease (i) all of the Premises, if
Tenant's Notice specifies a proposed assignment, or (ii) the portion of the
Premises described in Tenant's Notice, if Tenant's Notice specifies a proposed
sublease, which exclusion shall be effective as of the proposed effective date
of assignment or the proposed commencement date of sublease, as the case may
be, as specified in Tenant's Notice.  Landlord may exercise said option by
giving Tenant written notice within 20 days after receipt by Landlord of
Tenant's Notice of the proposed assignment or sublease.  If Landlord exercises
said option, Tenant shall surrender possession of the space to be excluded from
this Lease on the effective date of exclusion of said space from this Lease,
and neither party hereto shall have any further rights or liabilities with
respect to said space under this Lease except as otherwise specified in this
Lease.  Effective as of the date of exclusion of any portion of the Premises
covered by this Lease pursuant-to this paragraph: (i) the Monthly Base Rent
specified in l.0lH shall be reduced in the same proportion as the number of
square feet as determined by Landlord of the portion of the Premises so
excluded bears to the number of square feet as determined by Landlord of the
Premises immediately prior to such exclusion; (ii) the square feet of the
Premises specified in 1.01 I shall be decreased by the number of square feet as
determined by Landlord of the portion of the Premises so excluded; (iii)
Tenant's Proportionate Share shall be adjusted accordingly; and (iv) there
shall be no restrictions on Landlord reletting the portion of the Premises so
excluded to any other tenant, including, without limitation, any proposed
sublessee or assignee of Tenant.  If Landlord does not exercise said option,
Tenant may not thereafter enter into a sublease., for space which is different
than the space designated in Tenant's Notice, or for a term commencing on a
date other than the date designated in Tenant's Notice, nor may Tenant enter
into a sublease for the space designated in Tenant's Notice after the date
which is 120 days after the date that Tenant's Notice is delivered to Landlord,
nor may Tenant assign this Lease effective after a date which is 120 days after
the date that Tenant's Notice is delivered to Landlord, without again complying
with the provisions of this Paragraph 8.02 and affording Landlord the right to
recapture space as hereinabove provided.

                                       9.

                             MAINTENANCE AND REPAIR

9.01      LANDLORD'S MAINTENANCE AND REPAIR

Subject to the provisions of 5.03, 9.02, 26.07 and the other provisions of this
Lease,Landlord, at its expense, shall maintain and make necessary repairs to
the structural elements and exterior windows of the Building and the standard
electrical, plumbing, heating, ventilation and air conditioning systems located
in the Building; provided, however:

                 (1) Landlord shall not be responsible for the maintenance or
                     repair of any such systems which are located within the
                     Premises and are supplemental or special to the Building's
                     standard systems;


                                     Page 6
<PAGE>   12



Notwithstanding anything contained herein to the contrary, Tenant shall have
the right to assign this Lease or sublease the premises, or any part thereof,
to an "affiliate" without the prior written consent of Landlord, bit upon not
less than 10 days' prior written notice to Landlord and subject to all of the
other provisions of this Lease, specifically including, without limitation, the
continuation of liability of Tenant under this Lease.  For purposes of this
Lease, "affiliate" shall mean any person, corporation or other entity
controlling, controlled by, or under common control with Spyglass, Inc., an
Illinois corporation ("Spyglass") (or any successor to Spyglass as a result of
merger or consolidation, or any purchaser of all or substantially all -the
assets of Spyglass).  The term "control" as used herein shall mean the
possession, direct or indirect, of the power to direct or cause the direction
of the management and policies of such controlled entity through the ownership,
directly or indirectly, of more than fifty percent (50%) of the voting or
equity securities in any such controlled entity.  In the event of an assignment
of this Lease, the assignee shall expressly assume the obligations of the
Tenant under this Lease pursuant to a written assumption agreement delivered
to, Landlord.


                                    Page 6a
<PAGE>   13

          (2)    Landlord shall not be responsible for any maintenance
          or repair of any floor or wall coverings; and

          (3)  the cost of performing any of maintenance or repair caused by
          the negligence or act of Tenant, its employees, agents, servants,
          licensees, subtenants, contractors or invitees, or the failure of
          Tenant to perform any of its obligations under this Lease, shall be
          paid by Tenant (but only to the extent such costs are not covered by
          Landlord's insurance).

Notwithstanding the foregoing provisions of this Paragraph 9.01, nothing in
this Paragraph 9.01 shall affect or reduce Tenant's obligation to pay any
escalation in Operating Expenses as set forth in 22.02 of this Lease.

  9.02 TENANTS MAINTENANCE AND REPAIR

          Tenant, at its expense, shall keep, maintain and repair premises and
all contents therein in good order and operating condition (ordinary wear and
tear and damage by fire or other casualty excepted) and in accordance with all
applicable legal, governmental and quasi- governmental requirements, ordinances
and rules (including the Board of Fire Underwriters).  By way of inclusion and
not limitation, Tenant, at its expense, shall maintain and repair in good
operating condition the electrical, lighting, plumbing, heating, ventilating
and air conditioning systems in the Premises which are supplemental or special
to the Building's standard systems, and Tenant shall pay for all maintenance,
repair and replacement of all lighting fixtures', electrical switches,
electrical outlets, lamps, bulbs, tubes, ballasts and starters in the Premises.

                                      10.

     ALTERATIONS AND IMPROVEMENTS SUBSEQUENT TO INITIAL OCCUPANCY

10.01       TENANT'S ALTERATIONS SUBSEQUENT TO INITIAL OCCUPANCY

                 Tenant shall not, without the prior written consent of
         Landlord, make or cause to be made any alterations, improvements,
         additions or installations in or to the Premises subsequent to the
         initial occupancy of the Premises by Tenant*.  If Landlord so
         consents, before commencement of any such work or delivery of any
         materials into the Premises or the Building, Tenant shall furnish to
         Landlord for approval: architectural plans and specifications, names
         and addresses of all contractors, contracts, necessary permits and
         licenses, certificates of insurance and instruments of indemnification
         against any and all claims, costs, expenses, damages and liabilities
         which may arise in connection with such work, all in such form and
         amount as may be satisfactory to Landlord.  In addition, prior to
         commencement of any such work or delivery of any materials into the
         Premises, Tenant shall provide Landlord with evidence reasonably
         satisfactory to Landlord of Tenant's ability to pay for such work and
         materials in full, and, if requested by Landlord,** shall deposit with
         Landlord at such time such security for the payment of said work and
         materials as Landlord may require.  Tenant agrees to hold Landlord,
         its partners, the managing agent of the Building and each of their
         respective agents and employees forever harmless against all claims
         and liabilities of every kind, nature and description which may arise
         out of or in any way be connected with such work.  All such work shall
         be performed only by union contractors or mechanics approved by
         Landlord and which are licensed, bonded and insured under policies
         satisfactory to Landlord.  Such work shall be performed at such time
         during normal business hours and in such manner as Landlord may from
         time to time designate.  Tenant's agents, contractors, workmen,
         mechanics and suppliers shall work in harmony and not interfere with
         Landlord's agents, and contractors or the general operation of the
         Building.  If at any time such work shall cause or threaten to cause
         disharmony or interference, including labor disharmony, Landlord may
         revoke Tenant's authority to continue to perform such work.  Tenant
         shall pay the cost of all such work.  Upon completion of such work,
         Tenant shall furnish Landlord with contractors' affidavits and full
         and final waivers of lien and receipted bills covering all labor and
         materials expended.  All such work shall be in compliance with all
         applicable legal, governmental and quasi-governmental requirements,
         ordinances and rules (including the Board of Fire Underwriters), and
         ail requirements of applicable insurance companies.  All such work
         shall be done in a good and workmanlike manner and with the use of
         good grades of materials.  Tenant shall permit Landlord, if Landlord
         so desires, to supervise construction operations in connection with
         such work; (at no charge to Tenant except as provided in Section 26.14
         below) provided, however, that such supervision or right to supervise
         by

                                                                     Page 7
         *, ** See Insert an Page 7A
<PAGE>   14



*Notwithstanding the foregoing, Tenant may without Landlord's prior written
consent and without providing architectural plans and names of contractors to
Landlord, but subject to all of the other provisions of this Article 8, make
decorative or cosmetic changes to the Premises (e.g. painting, wall coverings,
floor coverings and hanging of pictures), provided that each such change or
series of related changes, (a) is non-structural, (b) does not affect any
mechanical, electrical or plumbing systems, fixtures or equipment, (c) is not
visible from the exterior of the Building, (d) does not cost in excess of
$10,000, and (d) does not require the issuance of a building permit.

**and if the cost of the alteration will exceed $15,000,





                                    Page 7A
<PAGE>   15

Landlord shall not constitute any warranty by Landlord to Tenant of the
adequacy of the design, workmanship or quality of such work or materials for
Tenant's intended use or impose any liability upon Landlord in connection with
the performance of such work*.  All alterations, improvements, additions and
installations to or on the Premises shall (subject to Article 13) become part
of the Premises at the time of their installation and shall remain in the
Premises at the expiration or termination of this Lease, or termination of
Tenant's right of possession of the Premises, without compensation or credit to
Tenant,

10.02 LIENS

  Tenant shall not permit any lien or claim for lien of any mechanic, laborer
or supplier or any other lien to be filed against the Building, the real estate
on which the Building is located, the Premises, or any part of such property
arising out of work performed, or alleged to have been performed by, or at the
direction of, or on behalf of Tenant.  If any such lien or  claim for lien is
filed Tenant shall within 30 days after such filing either have such lien or
claim for lien released of record or shall deliver to Landlord a bond or other
security in form, content, amount, and issued by a company satisfactory to
Landlord indemnifying Landlord, its partners, the managing agent of the
Building and others designated by Landlord against all costs and liabilities
resulting from such lien or claim for lien and the foreclosure or attempted
foreclosure thereof.  If Tenant fails to have such lien or claim for lien so
released or to deliver such bond to Landlord, Landlord, in addition to the
other rights and remedies under this Lease and without investigating the
validity of such lien, may pay or discharge the same and Tenant shall reimburse
Landlord upon demand for the amount so paid by Landlord, including Landlord's
expenses and reasonable attorneys' fees.


                                      11.

                       WAIVER OF CLAIMS AND INDEMNITY

11.01 WAIVER

         To the full extent permitted by law, Tenant hereby releases and waives
all claims against Landlord, its beneficiary, the managing agent of the
Building and each of their respective officers, directors, agents and employees
for injury or damage to person, property or business sustained in, on or about
the Building or the Premises or Lot 3 of the Resubdivision of Lot 3 in the
Naperville Corporate Center Subdivision in Naperville, Illinois by Tenant, its
agents or employees other than damage caused by the negligence of Landlord, its
beneficiary, the managing agent of the Building, or any of their respective
agents or employees.  To the full extent permitted by law, Tenant hereby waives
trial by jury in any action, proceeding or counterclaim brought by Landlord
against Tenant on any matter whatsoever arising out of or in any way connected
with this Lease, the relationship of Landlord and Tenant, Tenant's use of or
occupancy of the Premises and/or any emergency, statutory or other remedy.  To
the full extent permitted by law, Tenant agrees that, in the event Landlord
commences any summary proceeding for possession of the Premises, Tenant will
not interpose any counterclaim of any nature or description in any such
proceeding.

11.02     INDEMNIFICATION

       Tenant agrees to indemnify and hold harmless Landlord, its beneficiary,
the managing agent of the Building, and each of their respective officers,
directors, agents and employees, from and against any and all liabilities,
claims, demands, costs and expenses of every kind and nature (including
attorneys' fees), including those arising from any injury or damage to any
person, property or business, sustained in, on or about the Premises, the
Building or such Lot 3 of the Resubdivision of Lot 3,and (a)resulting from the
negligence of tenant, its employees, agents, servants, invitees, licensees or
subtenants, or (b)resulting from the failure of Tenant to perform its
obligations under this Lease; provided, however, Tenant's obligations under
this Paragraph shall not apply to injury or damage resulting from the
negligence of Landlord, its beneficiary, the managing agent of the Building, or
any of their respective officers, directors, agents or employees,*** If any
such proceeding is brought against Landlord, its beneficiary, the managing
agent of the Building, or any of their respective officers, directors, agents
or employees, Tenant covenants to defend such

 *, **,*** See Insert on Page 8A

                                     Page 8
<PAGE>   16

*If Landlord elects to supervise construction operations, Landlord's
supervision shall not unreasonably impede or delay the progress of the work.

**unless Landlord advises Tenant at the time of Landlord's consent to any
alteration that Landlord will require Tenant to remove same at the expiration
or termination of this Lease, in which event Tenant, at its expense, shall
remove same at the expiration or termination of this Lease and repair all
damage caused by the installation or removal of such alteration.

***or damage covered by insurance carried by Landlord (or required to be
carried by Landlord under this Lease).





                                    Page 8A
<PAGE>   17

          proceeding at its sole cost by legal counsel reasonably satisfactory
          to Landlord, if requested by Landlord.

                                      12.

                              LANDLORD'S REMEDIES

12.01     EVENTS OF DEFAULT

           Each of the following shall constitute an event of default by 
Tenant under this Lease: 

           Tenant fails to pay any installment of Rent when due,; Tenant fails
to observe or perform any of the other covenants, conditions or provisions of
this Lease be observed or performed by Tenant and fails to cure such default
within 30 days after written notice to Tenant**; the interest of Tenant in this
Lease is levied upon under execution or other legal process; a petition is
filed by or against Tenant to declare Tenant bankrupt or seeking a plan of
reorganization or arrangement under any Chapter of the Bankruptcy Code, or any
amendment, replacement or substitution therefor or to delay payment of, reduce
or modify Tenant's debts, or any petition is filed or other action taken to
reorganize or modify Tenant's capital structure or to dissolve Tenant; Tenant
is declared insolvent by law or any assignment of Tenant's property is made for
the benefit of creditors; a receiver is appointed for Tenant or Tenant's
property; (and such petition is not vacated witin 60 days after same is filed)
        

 12.02    LANDLORD'S REMEDIES

         Upon the occurrence of an event of default by Tenant under this Lease,
Landlord, at its option, without further notice or demand to Tenant, may in
addition to all other rights and remedies provided in this Lease, at law or in
equity:
        
 A.      Terminate this Lease and Tenant's right of possession of the Premises,
and recover all damages to which Landlord is entitled under law.  Landlord's
damages shall specifically include, without limitation (1) all Landlord's
expenses of reletting (including repairs, alterations, improvements, additions,
decorations, legal fees and brokerage commissions), plus (2) the aggregate sum
which at the time of such termination represents the excess, if any, of the
present value of the aggregate Adjusted Monthly Base Rent which would have been
payable by Tenant under this Lease for the balance of the Term (conclusively
presuming that adjustments to Monthly Base Rent on account of increases in
Taxes and Operating Expenses shall increase at the average annual rate of
increase thereof during the portion of the Term occurring prior to the
termination date but not exceeding 3 years), over the then present value of the
then aggregate fair rental value of the Premises for the balance of the Term
(allowing for a reasonable period of exposure on the open market before
realization of such fair rental value and deducting the then market tenant
concessions such as rent abatements and construction allowances), such present
value to be computed in each case on the basis of a 3% per annum discount from
the respective dates upon which such rentals would have been payable hereunder
had this Lease not been terminated.  The amount set forth in the preceding
sentence shall be automatically considered accelerated and immediately due and
payable in full by Tenant to Landlord upon Landlord's election to terminate
this Lease.  Landlord's right to terminate this Lease may also be exercised at
any time after the election by Landlord under Paragraph B below to terminate
Tenant's right to possession of the Premises.
        
 B.      Terminate Tenant's right of possession of the Premises without
terminating this Lease, in which event Landlord shall use reasonable efforts
to, relet the Premises, or any part thereof for the account of Tenant, for such
rent and term and upon such terms and conditions as are*** For purposes of such
reletting, Landlord is authorized to decorate, repair, alter and improve the
Premises to the extent reasonably necessary. If Landlord does not relet the
Premises, then Tenant shall pay Landlord monthly on the first day of each month
during the period that Tenant's right of possession is terminated, a sum equal
to the amount of Rent due under this Lease for such month (less any amount
which Landlord could have realized if Landlord relet the Premises to a
        
*, **, *** See Insert on Page 9A

                                   Page 9
<PAGE>   18

*and with respect only to each of the first two (2) such failures occurring in
any year of the Term, such failure continues for 5 days after Landlord gives
Tenant written notice of such failure-,

**provided, however, that if such failure is not susceptible to being cured
within such 30-day period and Tenant immediately commences such cure, such
30-day period shall be extended so long as Tenant is actively, diligently and
continuously attempting to effectuate such cure (but in no event shall said
30-day period be extended by more than an additional 30 days).

***commercially reasonable under the circumstances; provided, however, that
Landlord shall not be obligated to relet or attempt to relet the Premises on a
priority basis over other unleased or unoccupied space in the Building or in
other buildings then comprising the Naperville Corporate Center.





                                   Page 9A
<PAGE>   19

reputable, creditworthy substitute tenant procured by Tenant and presented to
Landlord in writing, which substitute tenant was ready, willing and able to
lease the entire Premises from Landlord under a lease in form identical to the
form of this Lease).  If the Premises are relet and a sufficient sum is not
realized from such reletting after payment of all Landlord's expenses of
reletting (including repairs, alterations, improvements, additions,
decorations, legal fees and brokerage commissions) to satisfy the payment of
Rent due under this Lease for any month, Tenant shall pay Landlord any such
deficiency monthly upon demand.  Tenant agrees that Landlord may file suit to
recover any sums due to Landlord under this section from time to time and that
such suit or recovery of any amount due Landlord shall not be any defense to
any subsequent action brought for any amount not previously reduced to judgment
in favor of Landlord.  If Landlord elects to terminate Tenant's right to
possession only without terminating this Lease, Landlord may, at its option,
enter into the Premises, remove Tenant's signs and other evidences of tenancy,
and take and hold possession thereof, as stated in Article 13; provided,
however, that such entry and possession shall not terminate this Lease or
release Tenant, in whole or in part, from Tenant's obligation to pay the Rent
reserved hereunder for the full Term or from any other obligation of Tenant
under this Lease.

12.03           TRUSTEE IN BANKRUPTCY

In the event a petition is filed by or against Tenant seeking a plan of
reorganization or arrangement under any Chapter of the Bankruptcy Code,
Landlord and Tenant agree, to the extent permitted by law, that the trustee in
bankruptcy shall determine within 60 days after commencement of the case,
whether to assume or reject this Lease.

12.04         ATTORNEYS' FEES

         Tenant shall pay upon demand, all costs and expenses, including
reasonable attorneys' fees, incurred by Landlord in enforcing Tenant's
obligations under this Lease or resulting from Tenant's default under this
Lease.


                                      13.

                             SURRENDER OF PREMISES

         Upon the expiration or termination of this Lease or termination of
Tenant's right of possession of the Premises, Tenant shall surrender and vacate
the Premises immediately and deliver possession thereof to Landlord in a clean,
good and tenantable condition, ordinary wear and damage by casualty loss
excepted.  Upon any, termination which occurs other than by reason of Tenant's
default, Tenant shall be entitled to remove from the Premises prior to such
termination all moveable trade fixtures and personal property of Tenant without
credit or compensation from Landlord, provided Tenant immediately shall repair
all damage resulting from such removal and shall restore the Premises to a
tenantable condition.  In the event possession of the Premises is not
immediately delivered to Landlord or if Tenant shall fail to remove any
moveable trade fixtures or personal property which Tenant is entitled to
remove, Landlord may remove same without any liability to Tenant.  Any moveable
trade fixtures and personal property which may be removed from the Premises by
Tenant but which are not so removed, and all improvements made by Tenant to the
Premises, shall be conclusively presumed to have been abandoned by Tenant and
title to such property shall pass to Landlord without any payment or credit,
and Landlord may, at its option and at Tenant's expense, store, keep and/or
dispose of such property.


                                      14.

                                  HOLDING OVER

         Tenant shall pay Landlord the fair rental value of the Premises, as
determined by Landlord (but in no event less than 150% of the Adjusted Monthly
Base Rent the first   then-applicable under this Lease) for the first month or
partial month during which Tenant retains possession of the Premises, or any
part of the Premises, after the expiration or termination of this Lease,
and 200% of the fair rental value of the Premises, as determined by Landlord
(but in no event less than 200% of the Adjusted monthly Base Rent then
applicable under this Lease) for each subsequent month or partial month during
which Tenant retains, possession of the Premises, or any part of the Premises,
after the expiration or termination of this lease.  Tenant shall also 
indemnify Landlord against all liabilities and

                                    Page 10

 





<PAGE>   20


damages sustained by Landlord by reason of any such retention of possession.
The provisions of this Article shall not constitute a waiver by Landlord of any
re-entry rights of Landlord available under this Lease or by law.  If Tenant
retains possession of the Premises, or any part of the Premises, for 30 days
after the expiration or termination of this Lease, then Landlord, at Landiord's
election expressed in written notice to Tenant but not otherwise, may, in
addition to all other rights and remedies available to Landlord under this
Lease, constitute such holding over- as a renewal of this Lease for a period of
one year on the same provisions as are set forth in this Lease, but for a
Monthly Base Rent equal to the then fair monthly base rental value of the
Premises, as determined by Landlord (but in no event less than the Monthly Base
Rent then payable by Tenant under this Lease).


                                      15.

                        DAMAGE BY FIRE OR OTHER CASUALTY

15.01       SUBSTANTIAL UNTENANTABILITY

If either the Premises or the Building is rendered substantially untenantable
by fire or other casualty, Landlord may elect by giving Tenant written notice
within 90 days after the date of said fire or casualty, either to:

                  (1)    terminate this Lease as of the date of the fire or 
         other casualty; or

                  (2)     proceed to repair or restore the Premises or the
         Building, other than leasehold improvements and personal property
         installed by Tenant, to substantially the same condition as existed
         immediately prior to such fire or casualty.

If Landlord elects to proceed pursuant to subsection (2) above, Landlord's
notice shall contain Landlord's reasonable estimate of the time required to
substantially complete such repair or restoration.  If such estimate indicates
that the time so required will exceed 180 days from the date of the casualty,
then Tenant shall have the right to terminate this Lease as of the date of such
casualty by giving written notice to Landlord not later than 20 days after the
date of Landlord's notice.  If Landlord's estimate indicates that the repair or
restoration can be substantially completed within 180 days, or if Tenant fails
to exercise its said right to terminate this Lease, this Lease shall remain in
force and effect, See Insert 1 on page 11A).  

15.02       INSUBSTANTIAL UNTENANTABILITY

            If the Premises are damaged by fire or other casualty but is not
rendered substantially untenantable, then Landlord shall diligently proceed to
repair and restore the damaged portions thereof, other than the leasehold
improvements and personal property installed by Tenant, to substantially, the
same condition as existed immediately prior to such fire or casualty, unless
such damage occurs during the last 12 months of the Term, in which event
Landlord shall have the right to terminate this Lease as of the date of such
fire or other casualty by giving written notice to Tenant within 30 days after
the date of such fire or other casualty. (See Insert 2 on Page 11A)

15.03       RENT ABATEMENT

         If all or any part of the Premises are damaged by fire or other
casualty and this Lease is not terminated, Adjusted Monthly Base Rent shall
abate for all or that part of the Premises which are untenantable on a per diem
and proportionate area basis from the date of the fire or other casualty until
Landlord has substantially completed the repair and restoration work in the
Premises which it is required to perform, provided, that as a result of such
fire or other casualty, Tenant does not occupy the portion of the Premises
which are untenantable during such period.

15.04       DEFINITIONS

(See Insert 3 on Page 11A)
                                    Page 11
<PAGE>   21

INSERT 1

provided, however, that if the repair or restoration is not substantially
completed within 180 days after the date of commencement of such repair or
restoration work (subject to 26.07), then Tenant shall have the right to
terminate this Lease by giving written notice to Landlord not later than 20
days after the expiration of said 180-day period.

INSERT 2

If the repair or restoration is not substantially completed within 90 days
after the date of commencement of such repair or restoration work (subject to
26.07), then Tenant shall have the right to terminate this Lease by, giving
written notice to Landlord not later than 20 days after the expiration of said
90-day period.

INSERT 3

As used in this Article 15 "substantial untenantability" shall mean 40% or more
of the rentable area of the Premises is rendered untenantable.





                                    Page 11A
<PAGE>   22

                                      16.

                                 EMINENT DOMAIN

16.01    SUBSTANTIAL TAKING

         If all or any part of the Premises or the Building is permanently
taken or condemned by any competent authority for any public use or purpose
(including a deed given in lieu of condemnation), which renders the Premises
substantially untenantable, this Lease shall terminate as of the date title
vests in such authority, and Adjusted Monthly Base Rent shall be apportioned as
of said date.

16.02    INSUBSTANTIAL TAKING

         If any part of the Premises or the Building is taken or condemned
for any public use or purpose (including a deed given in lieu of condemnation)
and this Lease is not terminated pursuant to 16.01, Adjusted Monthly Base Rent
shall be reduced for the period of such taking by an amount which bears the
same ratio to Adjusted Monthly Base Rent then in effect as the number of square
feet as determined by Landlord of the Premises so taken or condemned, if any,
bears to the number of square feet of the Premises specified in 1.01I.
Landlord, upon receipt and to the extent of the award in condemnation or
proceeds of sale, shall make necessary repairs and restorations (exclusive of
leasehold improvements and personal property installed by Tenant) to restore
the Premises remaining to as near its former condition as circumstances will
permit, and to the Building to the extent necessary to constitute the portion
of same not so taken or condemned as a complete architectural unit.  In the
event of any taking or condemnation described in this 16.02, the square feet of
the Premises stated in 1.01I and the square feet of the Building stated in
1.01L shall be reduced, respectively, by the number of square feet as
determined by Landlord of the portion of the Premises, if any, and the
Building, if any, so taken or condemned, and Tenant's Proportionate Share shall
be adjusted accordingly, for all purposes under this Lease.

16.03    COMPENSATION

         Landlord shall be entitled to receive the entire price or award from
any such sale, taking or condemnation without any payment to Tenant, and Tenant
hereby assigns to Landlord Tenant's interest, if any, in such award.  Tenant
shall have no claim or right to any price or award as a result of any such
sale, taking or condemnation because of this Lease or the unexpired term of
this Lease or the premature termination of this Lease or any option to extend
the term of this Lease or to lease additional space in the Building, (See
Insert 1 on Page 12A) 

16.04    DEFINITION (See Insert 2 on Page 12A)

                                      17.

                             TENANT'S INSURANCE

         Tenant, at its expense, shall maintain in force during the Term:

                 (1)      comprehensive general public liability insurance,
         which shall include coverage for personal liability, contractual
         liability, tenant's legal liability, bodily injury, death and property
         damage, all on an occurrence basis with respect to the business
         carried on, in or from the Premises and Tenant's use and occupancy of
         the Premises, with coverage for any one occurrence or claim of not
         less than $1,000,000 or such other amount as Landlord may reasonably
         require upon not less than six months' prior written notice, which
         insurance shall include Landlord, its partners and the managing agent
         of the Building as named insureds and shall protect Landlord in
         respect of claims by Tenant as if Landlord were separately insured;
         and

                 (2)      insurance against such other perils and in such
         amounts as Landlord may from time to time reasonably require upon not
         less than 30 days' prior written notice, such requirement to be made
         on the basis that the required insurance is



                                    Page 12
<PAGE>   23

INSERT 1

provided, however, that Tenant may make a separate claim for the cost of
Tenant's trade.fixtures and relocation costs, so long as such claim does not
diminish Landlord's award.

INSERT 2

As used in this Article 16, "substantially untenantable" shall mean a taking
whereby 40% or more of the rentable area of the Premises is rendered
untenantable.





                                    Page 12A
<PAGE>   24

    customary at the time for prudent tenants of properties similar to the      
    Building in the Naperville, Illinois area.

            All insurance required to be maintained by Tenant shall be on terms
and with insurers reasonably acceptable to Landlord. Each of the aforesaid
policies shall contain an undertaking by the insurer that no material change
adverse to Landlord or Tenant will be made, and such policy will not lapse or
be cancelled, except after not less than 30 days' prior written notice to
Landlord of the intended change, lapse or cancellation.  Tenant shall furnish
to Landlord, if and whenever requested by it, certificates or other evidences
acceptable to Landlord as to the insurance from time to time effected by Tenant
and its renewal or continuation in force.  

17.02       See Insert on Page 13A

17.03       See Insert on Page 13A
                                      18.


                             RULES AND REGULATIONS

         Tenant agrees that Tenant and each of Tenant's employees, agents and
invitees shall comply with the following rules and regulations and with all
reasonable modifications and additions thereto which Landlord may from time to
time make: (1) Any sign, lettering, picture, notice or advertisement installed
within the Premises which is visible from the public corridors within the
Building shall be installed in such manner and be of such character and style
as Landlord shall approve in writing.  No sign, lettering, picture, notice or
advertisement shall be placed on any outside window or in a position to be
visible from outside the Building; (2) Tenant shall not use the name of the
Building for any purpose other than Tenant's business address; (3) Tenant shall
not use the name of the Building for Tenant's business address after Tenant
vacates the Premises; (4) Sidewalks, entrances, passages, courts, corridors,
halls, elevators and stairways in and about the Premises shall not be
obstructed nor shall objects be placed against glass partitions, doors or
windows which would be unsightly from the corridors of the Building or from the
exterior of the Building; (5) No animals, pets, bicycles or other vehicles
shall be brought or permitted to be in the Building or the Premises; (6) Room
to room canvasses to solicit business from other tenants of the Building are
not permitted; (7) Tenant shall not waste electricity, water or air
conditioning and shall cooperate fully with Landlord to assure the most
effective and efficient operation of the heating and air conditioning systems
of the Building.  All controls shall be adjusted only by authorized building
personnel; (8) All corridor doors shall remain closed at all times; (9) No
locks or similar devices shall be attached to any door except by Landlord and
Landlord shall have the right to retain a key to all such locks; except that
Tenant may elect to retain all keys to the door(s) to any high security room or
area in the Premises; provided, however (i) Landlord shall not be obligated to
provide janitorial service to such room or area and (ii) Tenant shall pay for
the repair of any damage to such door(s) caused by any emergency entry into
such room or area;  (10) Tenant assumes full responsibility for protecting the
Premises from theft, robbery and pilferage.  Except during Tenant's normal
business hours, Tenant shall keep all doors to the Premises locked and other
means of entry to the Premises closed and secured; (11) Only machinery or
mechanical devices of a nature directly related to Tenant's ordinary use of the
Premises shall be installed, placed or used in the Premises and the
installation and use of all such machinery and mechanical devices is subject to
the other rules contained in this Article 18 and the other portions of this
Lease; (12) All cleaning, repairing, janitorial, decorating, painting or other
services and work in and about the Premises shall be done only by authorized
Building personnel; (13) Safes, furniture, equipment, machines and other large
or bulky articles shall be brought to the Building and into and out of the
Premises at such times and in such manner as the Landlord shall direct
(including the designation of elevator) and at Tenant's sole risk and cost. 
Prior to Tenant's removal of such articles from the Building, Tenant shall
obtain written authorization of the office of the Building and shall present
such authorization to a designated employee of Landlord; (14) Tenant shall not
in any manner deface or damage the Building; (15) Inflammables such as
gasoline, kerosene, naphtha and benzene, or explosives or any other articles of
an intrinsically dangerous 

                                    Page 13

*except that Tenant may elect to retain all keys to the door(s) to any high
security room or area in the Premises; provided, however (i) Landlord shall not
be obligated to provide janitorial service to such room or area and (ii) Tenant
shall pay for the repair of any damage to such door(s) caused by any emergency
entry into such room or area;

<PAGE>   25

17.02       LANDLORD'S INSURANCE.

Landlord shall maintain in force during the Term:

               (1)      comprehensive general public liability insurance; and

               (2)      all risks (hazard) insurance and rent loss insurance 
                        on the Building.

17.03       RELEASE OF LIABILITY .AND WAIVER OF SUBROGATION

            Notwithstanding any provision in this Lease to the contrary, each
party hereto waives any and every claim which arises or may arise in its favor
and against the other party hereto, or anyone claiming through or under either
of them, by way of subrogation or otherwise, during the Term (or upon the
expiration or termination of the Term of this Lease) for any and all loss of,
or damage to, or condition of, the Premises, the Building and property located
on or within the foregoing, resulting from fire or any other casualty or peril
which would be insured under any fire and all-risk (or extended risk) property
damage insurance policy, or a peril which is actually insured, whether or not
such loss or damage is caused by the fault or negligence of the other party or
anyone for whom such other party may be responsible, or otherwise due to any
other cause for which such party would have liability under applicable laws,
and whether or not such insurance is in effect or the amount of coverage by
such insurance.  Such waivers shall be in addition to, and not in limitation or
derogation of, any other waiver or release contained in this Lease with respect
to any loss or damage to property of the parties hereto.  Inasmuch as the above
mutual waivers will preclude the assignment of any aforesaid claim by way of
subrogation (or otherwise) to an insurance company (or any other person), each
party hereto hereby agrees immediately to give to each insurance company which
has issued to its policies of fire and extended coverage insurance, written
notice of the terms of such mutual waivers, and to have such insurance policies
properly endorsed, if necessary, to prevent the invalidation of such insurance
coverages by reason of such waivers.

 *provided, however, that Tenant may install a coffee maker and microwave oven
for use solely by Tenant's employees and not for sale to the public;





                                    Page 13A
<PAGE>   26


nature are not permitted in the Building or Premises; (16) Tenant shall
ascertain from Landlord the maximum amount of electrical current which can
safely be used in the Premises, taking into account the capacity of the
electric wiring of the Building and the Premises and the needs of other
tenants, and shall not use more than such safe capacity.  Landlord's consent to
the installation of electrical equipment shall not relieve Tenant from the
obligation not to use more electricity than such safe capacity; (17) To the
extent permitted by law, Tenant shall not permit picketing or other union
activity involving its employees in the Building, except in those locations and
subject to time and other limitations as to which Landlord may give prior
written consent; (18) Tenant shall not enter into or upon the roof of the
Building or any storage, heating, ventilation, air-conditioning, mechanical or
elevator machinery housing areas; (19) Tenant shall not distribute literature,
flyers, handouts or pamphlets of any type in any of the common areas of the
Building, without the prior written consent of Landlord; (20) Tenant shall not
cook, otherwise prepare or sell any food or beverages in or from the
Premises; provided, however, that Tenant may install a coffee maker and
microwave oven for use solely by Tenant's employees and not for sale to the
public; (21) Tenant shall not permit the use of any apparatus for sound 
production or transmission in such manner that the sound so transmitted or
produced shall be audible or vibrations therefrom shall be detectable beyond
the Premises; (22) Tenant shall keep all electrical and mechanical apparatus
free of vibration, noise and air waves which may be transmitted beyond the
Premises; (23) Tenant shall not permit objectionable odors or vapors to emanate
from the Premises; (24) Tenant shall not place a load upon any floor of the
Premises exceeding the floor load capacity for which such floor was designed or
allowed by law to carry; (25) No floor covering shall be affixed to any floor
in the Premises by means of glue or other adhesive, unless the installation
procedure is approved by Landlord; and (26) Tenant shall comply with all rules
and regulations established by Landlord pursuant to clause (6) of Paragraph 19
of this Lease.  Landlord shall not be responsible for the violation of any of
the foregoing rules and regulations by other tenants of the, Building and shall
use reasonable efforts to enforce the same against other tenants, provided,
however, that Landlord shall not be obligated to institute any legal action or
proceeding to enforce same.

                                      19.

                               LANDLORD'S RIGHTS

         Landlord shall have the following rights exercisable without notice
(except as expressly provided to the contrary, in this Lease) and without being
deemed an eviction or disturbance of Tenant's use or possession of the Premises
or giving rise to any claim for set-off or abatement of Rent: (1) To change the
name or street address of the Building; provided, if any such change is
voluntarily made by Landlord (as opposed to one required by law) and Landlord
does not provide Tenant with at least 90 days prior written notice of such
change, then Landlord agrees to reimburse Tenant for the reasonable documented
out-of-pocket costs paid by Tenant to reprint Tenant's stationery and other
business materials which are then in stock and which are rendered obsolete by
reason of such change; (2) To install, affix and maintain all signs on the
exterior of the Building, the interior of the Building and/or on Lot 3 of the
Resubdivision of Lot 3 in the Naperville Corporate Center Subdivision in
Naperville, Illinois; (3) To designate and/or approve prior to installation,
all types of signs, window shades, blinds, drapes, awnings or other similar
items, and all internal lighting that may be visible from the exterior of the
Premises; (4) To display the Premises to prospective tenants at reasonable
hours during the last 12 months of the Term; (5) To change the
arrangement,size, configuration and/or decoration of entrances, exits, doors,
closets, atriums, storage areas, corridors, boiler rooms, mechanical rooms,
elevators, washrooms, hallways, lobbies, trash and rubbish areas and stairs in
or about the Building and to change the arrangement, size and/or configuration
of the parking areas, driveways, entrances, exits and all other areas on Lot 3
of the Resubdivision of Lot 3 in the Naperville Corporate Center Subdivision in
Naperville, Illinois, provided that no such change shall materially adversely
affect access to the Premises; (6) to establish such reasonable and appropriate
rules and regulations (in addition to those set forth in the preceding
Paragraph 18) as are satisfactory to Landlord for the use by Tenant and its
employees, guests and invitees of any of the areas set forth in the preceding
clause (5); (7) To grant to any party the exclusive right to conduct any
business or render any service in or to the Building, provided such exclusive  
right shall not operate to prohibit Tenant from using the Premises for the
purposes permitted hereunder; (8) To prohibit the placing of vending or
dispensing machines of any kind in or about the Premises; (9) To have access
for Landlord and other tenants of the Building to any mail chutes and boxes
located in or on the Premises according to the rules of the United States Post
Office; (10) To close the Building after normal business hours, except that
Tenant and its employees and invitees shall be entitled to admission to the
Building at all times under such regulations as Landlord prescribes; (11) To
take any and all reasonable measures, including inspections and repairs to the
Premises or to the Building,

                                    Page 14





<PAGE>   27


as may be necessary or desirable in the operation or protection thereof; (12)
To retain at all times master keys or pass keys to the Premises; (13) To
install, operate and maintain security systems which monitor, by closed circuit
television or otherwise, all persons entering and leaving the Building; (14) To
install and maintain pipes, ducts, conduits, wires and structural elements
located in the Premises which serve other parts or other tenants of the
Building; and (15) To amend this Lease upon the reasonable request of the
holder of any mortgage or trust deed now or hereafter existing encumbering the
Building to incorporate into this Lease the standard protections required by
such holder provided, however, that no such amendment shall operate to increase
the Rent owing under this Lease or to materially affect Tenant's rights or
obligations under this Lease. Tenant shall sign any such amendment; provided,
however, that if Tenant fails to execute and deliver to Landlord any amendment
pursuant to this clause (15) within ten (10) days after Landlord delivers a
copy thereof to Tenant, Tenant hereby irrevocably and unconditionally
designates Landlord as Tenant's agent and attorney-in-fact to execute any such
amendment for Tenant. It is hereby expressly agreed that the power of attorney
hereby granted by Tenant to Landlord pursuant to this clause (15) is a power
coupled with an interest, may not be revoked by Tenant and shall be binding on
Tenant and its successors and permitted assigns.

                                      20.

                              ESTOPPEL CERTIFICATE

         Tenant shall from time to time after the date of this Lease, upon not
less than 10 days' prior written request by Landlord, or any mortgagee or
ground lessor of the Building, or any prospective purchaser of the Building,
deliver to Landlord, or such mortgagee, ground lessor or purchaser, a statement
in writing signed by Tenant certifying:


        (1)   That this Lease is unmodified and in full force and effect or, if
    there have been modifications, that this Lease, as modified, is in full
    force and effect;

        (2)   The amount of Adjusted Monthly Base Rent then payable under this
    Lease and the date to which Rent has been paid;

        (3)   That Landlord is not in default under this Lease or any work
    letter agreement, or, if in default, a detailed description of such
    default(s);

        (4)   That Tenant is or is not in possession of the Premises, as the
    case may be; and

        (5)   Such other information as may be reasonably requested.


                                      21.

                             INTENTIONALLY DELETED







                                    Page 15

<PAGE>   28

                                      22.

                        ADJUSTMENTS TO MONTHLY BASE RENT

22.01     DEFINITIONS

For the purposes of this Article 22, the following words and phrases shall have
the following meanings:

A.   "Adjustment Date" shall mean each January 1 occurring within the Term.

B.   "Adjustment Year" shall mean each calendar year during which an Adjustment
     Date occurs.



         D.      "Operating Expenses" shall mean all costs, expenses and
disbursements of every kind and nature which Landlord shall pay or become
obligated to pay in connection with the management, operation, maintenance,
replacement and repair of the Building, all or any part of Lot 3 of the
Resubdivision of Lot 3 (and any other land which serves the Building) in the
Naperville Corporate Center Subdivision in Naperville, Illinois, and the
personal property, fixtures, machinery, equipment, systems and apparatus
located in, on or used in connection with such Building and/or land.  Operating
Expenses shall include, among other items, (i) management fees,(not to exceed
5% of stabilized rents), and (ii) current depreciation as determined by
Landlord of capital improvements to the Building made after December 31, 1989
which are required by law or which are reasonably necessary as determined by
Landlord for the operation, maintenance or repair of the Building or all or any
part of said Lot 3 of the Resubdivision of Lot 3 (and any other land which
serves the Building) in the Naperville Corporate Center Subdivision in
Naperville, Illinois or any other property described in the preceding sentence.
Notwithstanding the foregoing, Operating Expenses shall not include real estate
brokerage and leasing commissions or salaries of executives of Landlord's
managing agent senior to the person managing the Building; depreciation on
improvements made on or prior to December 31, 1989; interest or principal
payments on Landlord's debts; costs for which Landlord is reimbursed by any
tenant (other than through rent adjustment provisions in tenant leases), any
insurer or any other third party; costs of enforcement(including attorneys'
fees) of any lease; costs of renovation or improvement of any tenant Premises;
costs of remedying any violation of law existing prior to the Commencement
Date; costs of complying with any insurance requirement imposed prior to the
Commencement Date; or advertising expenses. 


         E.      "Taxes" shall mean all federal, state and local governmental
taxes, assessments and charges (including transit or transit district taxes or
assessments) of every kind or nature including without limitation general real
estate taxes, (but excluding special assessments levied or assessed prior to
December 31, 1989), which Landlord shall pay or become obligated to pay because
of or in connection with the ownership, leasing, management, control or
operation of the Building (including all or any portion of Lot 3 of the
Resubdivision of Lot 3 and any other land which serves the Building in the
Naperville Corporate Center Subdivision in Naperville, Illinois), or of the
personal property, fixtures, machinery, equipment, systems and apparatus
located therein or used in connection therewith (including any rental or
similar taxes levied in lieu of or in addition to general real and/or personal
property taxes).  For purposes hereof, Taxes for any year shall be Taxes which
are due for payment or paid in that year rather than Taxes which are assessed
or become a lien during such year.  There shall be included in Taxes for any
year the amount of all fees, costs and expenses (including reasonable
attorneys' fees) paid by Landlord during such year in seeking or obtaining in
good faith and in a commercially reasonable manner any refund or reduction of
Taxes.  Taxes in any year shall be reduced by the net amount of any tax refund
received by Landlord during such year.  Taxes shall not include any federal,
state or local sales, use, franchise, capital stock, inheritance, general
income, gift or estate taxes, except that if a change occurs in the method of
taxation resulting in whole or in part in the substitution of any such taxes,
or any other assessment, for any Taxes as above defined, such substituted taxes
or assessments.

         F.      "Tenant's Proportionate Share" shall mean the amount set forth
in 1.01M of this Lease.  Tenant's proportionate share is calculated by dividing
the number of square feet of


                                   page 16




<PAGE>   29

the Premises as set forth in 1.01I by the number of square feet of the Building
as set forth in 1.01L.

22.02 ADJUSTMENTS TO MONTHLY BASE RENT

         Effective as of each Adjustment Date to and including the day
immediately preceding the following Adjustment Date, Monthly Base Rent shall be
increased by an amount equal to one twelfth (1 /12th) of the sum of:

        (1)     Tenant's Proportionate Share of the excess of Taxes for the
    Adjustment Year in which such Adjustment Date occurs over Taxes for the
    calendar year 1998; 
    Plus

        (2)      Tenant's Proportionate Share of the excess of Operating
    Expenses for the Adjustment Year in which such Adjustment Date occurs over
    Operating Expenses for the calendar year 1998;

22.03       PROJECTIONS

For the purpose of calculating Taxes and Operating Expenses for any Adjustment
Year, Landlord may make reasonable estimates, forecasts or projections
(collectively, the "Projections") of Taxes and Operating Expenses for such
Adjustment.  Within approximately 60 days following each Adjustment Date,
Landlord shall deliver to Tenant a written statement setting forth the
Projections of Operating Expenses and Taxes for the Adjustment Year in which
such Adjustment Date occurs, and providing a calculation of the increase in
installments of Monthly Base Rent to become effective as of said Adjustment
Date; provided, however, that the failure of Landlord to provide any such
statement within said period shall not relieve Tenant from its obligation to
continue to pay Adjusted Monthly Base Rent at the rate then in effect under
this Lease, and, within ten days following the date on which Landlord delivers
such statement to Tenant, Tenant shall pay any increases in Monthly Base Rent
reflected thereby effective retroactively to the most recently preceding
Adjustment Date.

22.04       READJUSTMENTS

         On or about April 1st following the end of each Adjustment Year, or at
such later time as Landlord shall be able to determine the actual amounts of
Operating Expenses and Taxes for the Adjustment Year last ended, Landlord shall
notify Tenant in writing of such actual amounts.  If such actual amounts exceed
the Projections for such Adjustment Year, then Tenant shall, within 30 days
after the date of such written notice from Landlord, pay to Landlord an amount
equal to the excess of the Adjusted Monthly Base Rent payable for the
Adjustment Year last ended based upon actual Operating Expenses and Taxes for
such year over the total Adjusted Monthly Base Rent paid by Tenant during such
Adjustment Year.  The obligation to make such payments shall survive the
expiration or earlier termination of the Term.  If the total Adjusted Monthly
Base Rent paid by Tenant during such Adjustment Year exceeds the amount thereof
payable for such year based upon actual Operating Expenses and Taxes for such
Adjustment Year, then Landlord shall credit such excess to installments of
Adjusted Monthly Base Rent payable after the date of Landlord's notice until
such excess has been exhausted, or if this Lease shall expire prior to full
application of such excess, Landlord shall pay to Tenant the balance thereof
not theretofore applied against Rent.  No interest or penalties shall accrue on
any amounts which Tenant is obligated to pay to Landlord or which Landlord is
obligated to credit or pay to Tenant by reason of this Paragraph.





                                    Page 17


<PAGE>   30

22.05 BOOKS AND RECORDS

         Landlord shall maintain books and records showing Operating Expenses
and Taxes in accordance with sound accounting and management practices.  The
books and records shall be available to Tenant for inspection, upon prior
reasonable notice.  Such inspection shall take place, at Landlord's election,
either at (a) the offices of the Building or (b) the main office of Bellemead
Management Co., Inc., 280 Corporate Center, Four Becker Farm Road, Roseland,
New Jersey 07068.

22.06       NO DECREASES IN MONTHLY BASE RENT

Notwithstanding anything to the contrary contained in this Lease, Monthly Base
Rent shall not be adjusted or decreased pursuant to this Article 22 below the
amount set forth in 1.01H.

22.07 PARTIAL OCCUPANCY FOR OPERATING EXPENSES

         For the purpose of calculating Operating Expenses for the calendar
year 1998, if the average number of rentable square feet occupied by tenants
during the calendar year 1998 in the Building is less than 132,225 rentable
square feet, Landlord shall make a determination ("Landlord's 1998
Determination") of what the Operating Expenses for the calendar year 1998 would
have been if during the entire calendar year 1998 an average of 132,225
rentable square feet Were occupied by tenants in the Building.  Landlord's 1998
Determination shall be binding and conclusive upon Tenant and shall for all
purposes of this Lease be deemed to be the Operating Expenses for the calendar
year 1998. For the purpose of calculating Operating Expenses for any Adjustment
Year, if the average number of rentable square feet occupied by tenants during
such Adjustment Year in the Building is less than 132,225 rentable square feet,
Landlord shall make a determination ("Landlord's Adjustment Year
Determination") of what the Operating Expenses for such Adjustment Year would
have been if during all of such Adjustment Year an average of 132,225 rentable
square feet were occupied by tenants in the Building.  Landlord's Adjustment
Year Determination of Operating Expenses for any Adjustment Year shall be
binding and conclusive upon Tenant and shall for all purposes of this Lease be
deemed to be the Operating Expenses for such Adjustment Year.


                                      23.

                              REAL ESTATE BROKERS


         Tenant represents and warrants to Landlord that, except for the
brokers named in 1.01K, Tenant has not dealt with any real estate broker,
salesperson, or finder in connection with this Lease, and no such person
initiated or participated in the negotiation of this Lease, or showed the
Premises to Tenant.  Tenant agrees to indemnify, defend and hold harmless
Landlord, its partners, the managing agent of the Building and their respective
agents and employees from and against any and all liabilities and claims for
commissions and fees arising out of a breach of the foregoing representation
and warranty.  Landlord shall be responsible for the payment of all commissions
payable by reason of this Lease to the broker, if any, specified in 1.01K,
based upon the leasing commission policy of Landlord applicable to the Building
as of the date of this Lease.


                                      24.

                          SUBORDINATION AND ATTORNMENT

24.01       SUBORDINATION

This Lease and the rights of Tenant hereunder are expressly subject and
subordinate to any ground lease of the land underlying the Building now or
hereafter existing and all amendments, renewals, modifications and extensions
of and to any said ground lease, and to the lien of any one or more mortgage or
trust deed specified by Landlord now or hereafter existing encumbering the
Building, or any part thereof, or said


                                    Page 18


<PAGE>   31

land or ground leasehold estate, and all amendments, renewals, modifications
and extensions of and to each said mortgage or trust deed, and to all advances
made or hereafter to be made upon the security of each said mortgage or trust
deed.  Tenant agrees to promptly sign and deliver to Landlord such further
instruments subordinating this Lease to any such ground lease or to the lien of
each such mortgage or trust deed as may be requested in writing by Landlord
from time to time.

24.02 ATTORNMENT

In the event of the cancellation or termination of any such ground lease in
accordance with its provisions or by the surrender of such ground leasehold
estate, whether voluntary, involuntary or by operation of law, or by summary
proceedings, or the foreclosure of any such mortgage or trust deed by voluntary
agreement or otherwise, or the commencement of any judicial action seeking such
foreclosure, Tenant, at the request of the then Landlord, shall attorn to and
recognize such ground lessor, mortgagee, holder of such trust deed or purchaser
in foreclosure as Tenant's Landlord under this Lease.  Tenant agrees to sign
and deliver at any time upon request of such ground lessor, mortqagee., holder,
purchaser, or any of their successors, any instrument to further evidence such
attornment.


                                      25.

                                    NOTICES

         All notices required or permitted to be given under this Lease shall
be in writing and shall be deemed given and delivered, whether or not received,
on the date when personally delivered (and receipted for) or two days following
the date when deposited in the United States Mail, postage prepaid and properly
addressed, certified mail, return receipt requested, at the following
addresses:

        (1)    To Landlord: c/o Bellemead Management Co., Inc., 280 Corporate
    Center, Four Becker Farm Road, Roseland, New Jersey 07068 or such other
    address as Landlord shall designate by written notice to Tenant with copies
    to Property Manager, Bellemead Development Corporation, 1240 E.  Diehl Road,
    Naperville, Illinois 60563 and to Neil T. Neumark, Schwartz, Cooper,
    Greenberger & Krauss, 180 North LaSalle Street, Suite 2700, Chicago,
    Illinois 60601; and

        (2)    To Tenant: At the address specified in 1.01C prior to the
    Commencement Date, and at the Premises after the Commencement Date, or such
    other address as Tenant shall designate by written notice to Landlord.

Any notice given to Tenant by Bellemead Management Co., Inc., the managing
agent of the Building, shall be deemed as valid as if given by Landlord and
shall be binding upon Tenant.
                                      26.

                                 MISCELLANEOUS

26.01 LATE CHARGES

         All delinquent Rent shall bear interest at the maximum rate permitted
by law or 2% in excess of the Prime Rate as published by The First National
Bank of Chicago as in effect from time to time, whichever is less, from the
date due until paid.

26.02 ENTIRE AGREEMENT

This Lease and the Exhibits attached hereto contain the entire agreement
between landlord and Tenant concerning the Premises and there are no other
agreements, either oral or written, between Landlord and Tenant.




                                    Page 19


<PAGE>   32

26.03 NO OPTION

         The signing of this Lease by Tenant and delivery of same to Landlord
does not constitute a reservation of or option for the Premises or an agreement
by Landlord to enter into a Lease and this Lease shall become effective only if
and when Landlord signs and delivers this Lease to Tenant; provided, however,
the signing and delivery by Tenant of this Lease to Landlord shall constitute
an irrevocable offer by Tenant to lease the Premises on the terms and
conditions contained in this Lease, which offer may not be withdrawn or revoked
by Tenant for 10 business days after such signing and delivery to Landlord.  If
Tenant is a corporation, it shall deliver to Landlord, concurrently with the
delivery to Landlord of a copy of this Lease signed by Tenant, certified
resolutions of Tenant's directors authorizing the signing and delivery of this
Lease and the performance by Tenant of its obligations under this Lease.

26.04       ACCORD AND SATISFACTION

            No payment by Tenant or receipt by Landlord of a lesser amount than
any installment or payment of Rent due shall be deemed to be other than on
account of the amount due, and no endorsement or statement on any check or any
letter accompanying any check or payment of Rent shall be deemed an accord and
satisfaction, and Landlord may accept such check or payment without prejudice
to Landlord's right to recover the balance of such installment or payment of
Rent and Landlord may pursue any other remedies available to Landlord.  No
receipt of money by Landlord from Tenant after the termination of this Lease or
Tenant's right of possession of the Premises shall reinstate, continue or
extend the Term.

26.05     LIMITATION OF LIABILITY

          Notwithstanding anything to the contrary herein provided, each and
every term, covenant, condition and provision of this Lease is hereby made
specifically subject to the provisions of this Paragraph 26.05. The term
"Landlord" as used in this Lease means only the owner or lessor for the time
being of the Building, so that in the event of any conveyance of such interest
and the transfer to the transferee of any funds then being held under this
Lease by such owner, Landlord shall be and hereby is entirely freed and
relieved of any and all obligations of Landlord hereunder thereafter accruing,
and it shall be deemed without further agreement between the parties and such
grantee(s) that the grantee has assumed and agreed to observe and perform all
obligations of Landlord hereunder.  It is specifically understood and agreed
that notwithstanding anything to the contrary herein provided or otherwise
provided at law or in equity, there shall be absolutely no personal liability
in excess of its interest in tire Building to Landlord or any successor in
interest thereto (whether the same be an individual, joint venture, trust, land
trust, tenancy in common, firm or partnership, general, limited or otherwise)
or on the part of the members of any firm, partnership or joint venture or
other unincorporated Landlord with respect to any of the terms, covenants
and/or conditions of this Lease; in the event of a breach or default by
Landlord, or any successor in interest thereof, of any of its obligations under
this Lease, Tenant shall look solely to the then Landlord for the satisfaction
of each and every remedy of Tenant, such exculpation of personal and additional
liability which is in excess of such interest in the Building to be absolute
and without any exception whatsoever.

26.06       BINDING EFFECT

         This Lease shall be binding upon and inure to the benefit of Landlord
and its successors and assigns.  This Lease shall be binding upon and inure to
the benefit of Tenant and its successors and permitted assigns.

26.07       FORCE MAJEURE

         Landlord shall not be deemed in default with respect to any of the
terms, covenants, conditions and provisions of this Lease on Landlord's part to
be performed if Landlord fails to timely perform same and such failure is due
in whole or in part to any strike, lockout, labor trouble (whether legal or
illegal), civil disorder, inability to procure materials, failure of power,
restrictive governmental laws or regulations, riots, insurrections, war, fuel
shortages, accidents, casualties, Acts of God, acts caused directly or
indirectly by Tenant (or Tenant's



                                    Page 20


<PAGE>   33

agents, employees or invitees), mechanical breakdown, repair, servicing or any
other cause beyond the reasonable control of Landlord.

26.08       CAPTIONS

The Article and Paragraph captions in this Lease are inserted only as a matter
of convenience and in no way define, limit, construe, or describe the scope or
intent of such Articles and Paragraphs.

26.09       APPLICABLE LAW

         This Lease shall be construed in accordance with the laws of the State
of Illinois.

26.10       TIME

         Time is of the essence of this Lease and the performance of all
obligations hereunder.

26.11       LANDLORD'S RIGHT TO PERFORM TENANT'S DUTIES

If Tenant fails timely to perform any of its duties under this Lease Landlord
shall have the@ right (but not the obligation), after the expiration of any
notice and cure period or grace period elsewhere under this Lease expressly
granted to Tenant for the performance of such duty, to perform such duty on
behalf and at the expense of Tenant without further prior notice to Tenant, and
all sums expended or expenses incurred by Landlord in performing such duty
shall be deemed to be additional Rent under this Lease and shall be due and
payable upon demand by Landlord.

26.12       TENANT'S REMEDIES

         Tenant agrees that in the event of a default by Landlord under this
Lease, Tenant shall give written notice thereof to all mortgagees and ground
lessors of the Premises, or any interest therein, and a period of 30 days
within which to cure or cause to be cured such default, prior to proceeding to
enforce any rights or remedies of Tenant under this Lease.

26.13       RIDERS

         All Riders attached hereto and signed both by Landlord and Tenant
shall be deemed to be a part hereof and are hereby incorporated into this
Lease.

26.14       CONSENT

         In any and all cases where Landlord's consent or approval is required
under this Lease, Tenant shall, upon Landlord's demand, reimburse Landlord, as
additional rent, for all reasonable and appropriate costs and expenses,
including but not limited to architectural, engineering and legal fees, which
Landlord incurs in determining whether to grant its consent or approval.  See
Insert on page 21A.
                                      27.

                                    PARKING

         So long as Tenant is not in default under this Lease, Tenant and its
agents, invitees and employees shall have a license to use (in accordance with
the provisions of this Lease) in the aggregate 3.3 parking spaces in the
location specified by Landlord on Lot 3 of the Resubdivision of Lot 3 (and/or
on any other adjacent parcels of land designated by Landlord) in the Naperville
Corporate Center Subdivision in Naperville, Illinois for each 1,000 useable
square feet of the Premises (as determined by Landlord's architect) for the
purpose of parking automobiles used by any of such persons;* Provided,

                 (1)      neither Tenant nor its agents, invitees or employees
         shall use in the aggregate more than such number of parking spaces on
         such Lot 3 of the Resubdivision of Lot 3 (or adjacent parcels of
         land);

*6 of which said parking spaces shall be reserved parking spaces for Tenant's
exclusive use at a location designated by Landlord and the remainder of said
parking spaces shall be unreserved parking spaces;

                                    Page 21
<PAGE>   34

26.15 TERMINATION OPTION

         In the event Tenant vacates or abandons the Premises for a period of
at least 30 days, Landlord shall have the option to terminate this Lease,
without termination fee or penalty payable by or to Landlord or Tenant, by
giving Tenant written notice of termination at any time thereafter.





                                    Page 21A
<PAGE>   35

    (2)     Tenant acknowledges, understands and agrees that Landlord shall
not be liable or responsible for enforcing such license or preventing any
violation thereof; and
        
    (3)     Landlord shall have the right (in addition to all other remedies
available to Landlord under this Lease, at law or in equity) to revoke such
license in the event of any condemnation or taking by any lawful authority of
any part of such Lot 3 of the Resubdivision of Lot 3 which reduces the number
of parking spaces which serve the Building or in the event of any other
occurrence not caused by Landlord which reduces the number of parking spaces
which serve the Building or in the event of the use by Tenant or its agents,
invitees or employees in the aggregate of more than such number of parking
spaces which are hereby licensed to Tenant, or in the event of any default by
Tenant under this Lease or in the event Tenant uses parking spaces in an area
other than the area specified by Landlord.
        

<PAGE>   36

LANDLORD:                                         TENANT:
---------                                         -------

AMERICAN NATIONAL BANK AND TRUST         SPYGLASS, INC. an Illinois corporation
COMPANY OF CHICAGCO, not
personally, but solely as
Trustee under Trust Agreement
dated June 12, 1978 and known
as Trust No. 43194





Title.




*(4) Landlord shall not be obligated to "police" or enforce Tenant's exclusive
right to use said reserved parking spaces against other tenants, users or
invitees of the Building, nor to tow any unauthorized vehicle from said
reserved spaces; and 

(5)  if 20% or more of the unreserved parking spaces now serving the Building 
are taken or condemned for any public use or purpose (and the Premises are not
correspondingly reduced in area by reason of such taking or condemnation) and
if Landlord fails to provide or make available to Tenant comparable alternative
parking spaces elsewhere in the Naperville Corporate Center or in the general
vicinity of the Building, then Tenant may terminate this Lease by giving
Landlord written notice within 20 days after such taking or condemnation.
        




                                    Page 22


<PAGE>   37





                EXHIBIT A - Diagram of Fourth Floor (Floorplan)
                                    5/28/97


<PAGE>   38


                                  EXHIBIT C

                        BELLEMEAD MANAGEMENT CO., INC.

                            Cleaning Specification

<TABLE>
<CAPTION>
SERVICES TO BE PERFORMED                                        FREQUENCY
------------------------                                        ---------
COMMON AREAS, LOBBIES, ELEVATORS, ETC.
--------------------------------------
<S>                                                              <C>

1.  Sweep all flooring using a dust treated mop then wet mop.
    Remove all gum, tar, etc., from floors.                         Nightly
2.  Empty and damp clean ashtrays and screens.                      Nightly
3.  Clean and service ash urns.                                     Nightly
4.  Clean and sanitize drinking fountains.                          Nightly
5.  Spot clean entrance door glass.                                 Nightly
6.  Sweep all stairwells.  Remove all gum, tar, etc. from floors.   Nightly
7.  Elevator cab to be wiped clean.                                 Nightly
8.  Elevator floors to be vacuumed.                                 Nightly
9.  Vacuum elevator door tracks with a nozzle.                      Nightly
10. Lobby entrance doors and windows to be washed completely.       Weekly
11. Lobby walls, glass, etc., cleaned thoroughly.                   Weekly
12. Elevator cab to be thoroughly cleaned and polished.             Weekly
13. High dust all horizontal surfaces above hand height.            Monthly
14. Machine scrub all hard floors.                                  Monthly

                          RESTROOMS

1.  Sweep and wash all restroom floors using proper disinfectants.  Nightly

2.  Wash and polish all mirrors, powder shelves, bright work and
    enamel surfaces in all restrooms                                Nightly

3.  Scour, wash and disinfect all basins, bowls and urinals.        Nightly

4.  Wash and disinfect all toilet seats.                            Nightly

5.  Hand dust and clean, washing where necessary all partitions,
    tile, walls, dispensers and receptacles, in all restrooms.      Nightly

6.  Supply and fill all liquid soap dispensers, toilet paper
    holders and C-fold paper towel dispensers.                      Nightly

7.  Wash and sanitize all waste receptacles.                        Weekly

8.  Wet wipe all wall and stall surfaces.                           Weekly
</TABLE>

                                     C-1
                                                                          

<PAGE>   39

<TABLE>
<S>                                                                 <C>
9.  Machine scrub all floor surfaces with approved germicidal
    solution.                                                       Weekly

10. Flush all toilet bowls and urinals with Saniflush or equal.     Weekly

11. High dust all horizontal surfaces including shelves,
    ledges, moldings, pipes, ducts, heating outlets, etc.           Monthly

12. Wash and sanitize all metal partitions.                         Monthly


TENANT AREAS
------------

1.  Empty and clean all wastepaper receptacles, empty and damp
    wipe all ashtrays                                               Nightly
2.  Sweep and/or dust mop all non-carpeted areas, then wet mop.     Nightly
3.  Vacuum all carpeted areas.                                      Nightly
4.  All stone, ceramic tile, marble, terrazzo and other unwaxed
    flooring to be swept and wet mopped.                            Nightly
5.  Hand dust and wipe clean ill office furniture.                  Nightly
6.  Spot clean counters and desk tops for coffee stains, etc.       Nightly
7.  Wipe clean all brass and other bright work.                     Nightly
8.  Wash and disinfect all fountains and coolers.                   Nightly
9.  Dust and clean all sand urns. Replace sand as necessary.        Nightly
10. Hand dust chair rails, baseboard trim (low dusting only).       Nightly
11. Dust all leather or leather type furniture.                     Nightly
12. Dust all open closet shelving.                                  Nightly
13. All office furniture to be vacuumed with a nozzle.              Weekly
14. All closet shelving, coat racks, etc. to be dusted.             Weekly
15. Vacuum with a nozzle around the base of all walls, furniture,
    desks                                                           Weekly
16. Hand dust and wipe clean all window sills, wall paneling,
    partitions. Wash as required.                                   Weekly
17. Remove all finger marks from entrance doors, door frames, and
    switch plates.                                                  Weekly
18. Hand dust all door and other ventilating louvers.               Weekly

</TABLE>

WINDOW CLEANING - EIGHT TIMES PER YEAR
--------------------------------------

Window cleaning services will be rendered Monday through Friday during working
hours, except during legal holidays.

1. Wash all windows, inside and outside.
2. Wash interior glass partitions, transoms, etc.





                                      C-2