Document:

<PAGE>   1
                                                                    EXHIBIT 4.15

             SUPPLEMENTAL AGREEMENT TO BRIDGE LOAN TRANSACTION DATED
        AUGUST 10, 1999 (AS EXTENDED AND AMENDED TO DATE) BY AND BETWEEN
          LEXON TECHNOLOGIES, INC. ("DEBTOR"), CHICAGO MAP CORPORATION
             AND STEVEN PESKAITIS ("GUARANTORS"), AND MILLER CAPITAL
          CORPORATION, STEPHEN A. MCCONNELL, JOCK PATTON AND DICKERSON
                               WRIGHT ("LENDERS")

For and in consideration of $1.00, and other good and valuable consideration
provided by each of the parties hereto to each of the others, including
agreement to the following terms and conditions, the parties hereto agree this
30th of December, 1999 that the following terms and conditions are incorporated
in and made a part of the Securities Purchase Agreement, Notes, Security
Agreements, Guaranties and other instruments and documents ("Loan Documents")
executed and delivered at any time from and after August 10, 1999 in connection
with the above-captioned Bridge Loan Transaction as well as that certain
Engagement Letter dated July 26, 1999 relating to investment advisory services
provided to Debtor by Miller Capital Corporation ("MCC").

         o  Debtor will pay Lenders $150,000.00 in cash on or before January 31,
            2000.

         o  Debtor will pay the remaining principal balance of $600,000.00, plus
            interest at the rate of 12% per annum, in monthly payments of
            interest only for 6 months beginning March 1, 2000 and continuing on
            the 1st day of each month thereafter.

         o  Debtor will pay the remaining principal balance of $600,000.00, plus
            any accrued interest, on August 1, 2000, provided the Debtor has
            received debt or equity financing proceeds in an aggregate amount of
            $3,000,000 or more during the period commencing December 30, 1999
            and continuing through August 1, 2000, and limited to the extent
            such proceeds exceed $3,000,000. Any debt or equity financing
            proceeds received in an aggregate amount of less than $3,000,000.00
            during this period will be used for operations.

         o  If the Debtor has not received debt or equity financing proceeds in
            an aggregate amount of $3,600,000 or more during the period
            commencing December 30, 1999 and continuing through August 1, 2000,
            the Debtor will pay the remaining principal balance of $600,000.00,
            plus interest at the rate of 12% per annum, in six equal monthly
            payments of principal and interest beginning on August 1, 2000 and
            continuing on the 1st day of each month thereafter. Any debt or
            equity financing proceeds received after August 1, 2000, to the
            extent in excess of $3,000,000, will be applied first to payment in
            full of outstanding principal and interest to the Lenders.

         o  The Debtor will issue 300,000 shares of common stock to MCC for
            $1.00 of consideration with regard to termination of the Engagement
            Letter and 250,000 shares of common stock, for $1.00 of
            consideration, to Lenders in connection with the Loan Documents.

<PAGE>   2

         o  The Engagement Letter will terminate on December 30, 1999 and
            neither party thereto will have any continuing duty or obligation to
            the other, except that Debtor will pay a fee to MCC pursuant to the
            fee schedule set forth therein out of the proceeds, if any, received
            by Debtor from any equity or debt financing or investment by any of
            the parties introduced to Debtor by MCC and identified in the
            schedule attached hereto.

         o  MCC and the other Lenders will not subordinate any of the existing
            security interests and guarantees in favor of MCC and Lenders under
            the Loan Documents to any lender or investor ("New Lender") that at
            any time hereafter provides equity or debt financing or investment
            to Debtor, but hereby consents to and agrees to permit Debtor to
            incur any such new financing or investment with the grant of a
            security interest to such New Lender in and to any and all
            collateral under the Loan Documents, which security interest shall
            be pari passu with the Lender's debt, provided that: (i) the terms
            of such new debt provide that no principal payments can be made on
            the new debt until the Lender's debt has been repaid in full; and
            (ii) the amount of such new debt does not exceed $1,500,000. Lenders
            all agree to enter into a collateral sharing arrangement with such
            New Lender, pursuant to which the collateral currently securing the
            debt of the Lenders would also be permitted to secure the debt of
            the New Lender on a pari passu basis.

ACCEPTED AND AGREED THIS 30th day of December 1999.

On Behalf of MCC and Lenders:                     On Behalf of Debtor:

Miller Capital Corporation, Inc.                  LEXON Technologies, Inc.

By: /s/ Rudy P. Miller                            By: /s/ Steven Peskaitis
    --------------------------------                 ---------------------------
        Rudy P. Miller, CEO                               Steven Peskaitis,
                                                          President

                                                  On Behalf of Guarantors:

                                                  Chicago Map Corporation

                                                  By:  /s/ Steven Peskaitis
                                                     ---------------------------
                                                           Steven Peskaitis,
                                                           President

                                        2<PAGE>   1
                                                                    EXHIBIT 10.2

                           INDUSTRIAL BUILDING LEASE

Term of Lease:

         Beginning:        May 7, 1999
         Ending:           May 31, 2004

Monthly Rent:              SEE RIDER ATTACHED

Date of Lease:             June 1, 1999

Location of Premises:      OFFICE SPACE AT 1401 BROOK DRIVE,
                           DOWNERS GROVE, ILLINOIS  60515
                           PER DIAGRAM ATTACHED.

Purpose:                   GENERAL OFFICE USE

Lessee:

         Name:             CHICAGO MAP CORPORATION
         Address:          15419 EAST 127th STREET
         City:             LEMONT, ILLINOIS  60439

Lessor

         Name:             UNITED STATES BRASS & COPPER CO.
         Address:          1418 CENTRE CIRCLE DRIVE
         City:             DOWNERS GROVE, ILLINOIS 60515

In consideration of the mutual covenants and agreements herein stated, Lessor
hereby leases to Lessee and Lessee hereby leases from Lessor solely for the
above purposes designated above (the "Premises"), together with the
appurtenances thereto, for the above Term.

                         LEASE COVENANTS AND AGREEMENTS

1. RENT. Lessee shall pay Lessor or Lessor's agent as rent for the Premises the
sum stated above, monthly in advance, until termination of this lease, as
Lessor's address stated above or such other address as Lessor may designate in
writing.

2. CONDITION AND UPKEEP OF PREMISES. Lessee has examined and knows the condition
of the Premises and has received the same in good order and repair, except as
otherwise set forth in the Riders attached hereto and made a part hereof, and
acknowledges that no representations as to the condition and repair thereof have
been made by Lessor, or his agent, prior to or at the execution of this lease
that are not herein expressed. Lessee will

<PAGE>   2

keep the Premises, including all appurtenances, in good repair, replacing all
broken glass with glass of the same size and quality as that broken; and upon
the termination of this lease, in any way, will yield up to the Premises to
Lessor, in good condition and repair, loss by fire and ordinary wear excepted,
and will deliver the keys therefor at the place of payment of said rent.

3. LESSEE NOT TO MISUSE SUBLET; ASSIGN. Lessee will not allow Premises to be
used for any purpose that will increase the rate of insurance thereon, nor for
any purpose other than that hereinbefore specified, and will not load floors
with machinery or goods beyond the floor load rating prescribed by applicable
municipal ordinances, and will not allow the Premises to be occupied in whole,
or in part, by any other person, and will not sublet the same, or any part
thereof, nor assign this lease without in each case the written consent of the
Lessor first hand, and Lessee will not permit any transfer by operation of law
of the interest in Premises acquired through this lease, and will not permit
Premises to be used for any unlawful purpose, or for any purpose that will
injure the reputation of the building or increase the fire hazard of the
building, or disturb the tenants or the neighborhood, and will not permit the
same to remain vacant or unoccupied for more than ten consecutive days; and will
not allow any signs, cards or placards to be posted or placed thereon, nor
permit any alteration of or addition to any of the Premises, except by written
consent of Lessor; all alterations and additions to the Premises shall remain
for the benefit of Lessor unless otherwise provided in the consent aforesaid.

4. MECHANIC'S LIEN. Lessee will not permit any mechanic's lien or liens to be
placed upon the Premises or any building or improvement thereon during the term
hereof, and in case of the filing of such lien Lessee, will promptly pay same.
If default in payment thereof shall continue for thirty (30) days after written
notices thereof from Lessor to the Lessee, the Lessor shall have the right and
privilege at Lessor's option of paying the same or any portion thereof without
injury as to the validity thereof, and any amounts so paid, including expenses
and interest, shall be so much additional indebtedness hereunder due from Lessee
to Lessor and shall be repaid to Lessor immediately on condition of bill
therefor.

5. INDEMNITY FOR ACCIDENTS. Lessee covenants and agrees that he will protect and
save and keep the Lessor forever harmless and indemnified against and from any
penalty or damages of charges imposed for any violation of any laws or
ordinances, whether occasioned by the neglect of Lessee or those holding under
Lessee, and that Lessee will at all times protect, indemnify and save and keep
harmless the Lessor against and from any and all loss, cost, damage or expense,
arising out of or from any accident or other occurrence on or about the
Premises, causing injury to any person or property whichsoever or whatsoever and
will protect, indemnify and save and keep harmless the Lessor against and from
any and all claims and against and from any and all loss, cost, damage or
expense arising out of any failure of Lessee in any respect to comply with and
perform all the requirements and provision hereof.

                                       2
<PAGE>   3

6. NON-LIABILITY OF LESSOR. Except as provided by Illinois statute, Lessor shall
not be liable for any damage occasioned by failure to keep the Premises in
repair, nor for any damage done or occasioned by or from plumbing, gas, water,
sprinkler, steam or other pipes or sewage or the bursting, leading or running on
any pipes, tanks or plumbing fixture in, above, upon or about Premises or any
building or improvement thereon nor for any damage occasioned by water, snow or
ice being upon or coming through the roof, skylights, trap door or otherwise,
nor for any damages arising from acts or neglect of any owners or occupants of
adjacent or contiguous property.

7. WATER, GAS AND ELECTRIC CHARGES. Lessee will pay, in addition to the rent
above specified, all water rents, gas and electric light and power bills taxed,
levied or charged on the Premises, for and during the time for which this lease
is granted, and in case said water rents and bills for gas, electric light and
power shall not be paid when due, Lessor shall have the right to pay the same,
which amounts so paid, together with any sums paid by Lessor to keep the
Premises in a clean and healthy condition, as above specified, are declared to
be so much additional rent and payable with the installment of rent next due
thereafter.

8. KEEP PREMISES IN REPAIR. Lessor shall be obliged to incur any expense for
repairing any improvements upon said damaged premises or connected therewith,
and the Lessee at his own expense will keep all improvements in good repair
(injury by fire, or other causes beyond Lessee's control excepted) as well as in
good tenantable and wholesome condition, and will comply with all local or
general regulations, laws and ordinances applicable thereto, as well as lawful
requirements of all competent authorities in that behalf. Lessee will, as far as
possible, keep said improvements from deterioration due to ordinary wear and
from falling temporarily out of repair. If Lessee does not make repairs as
required hereunder promptly and adequately, Lessor may but need not make such
repairs and pay the costs thereof, and such costs shall be so much additional
rent immediately due from and payable by Lessee to Lessor.

9. ACCESS TO PREMISES. Lessee will allow Lessor, upon 48 hours prior written
notice, and during ordinary business hours, free access to the Premises for the
purpose of examining or exhibiting the same, or to make any repairs or
alterations thereof which Lessor may see fit to make and will allow to have
place upon the Premises at all times notice of "For Sale" and "To Rent", and
will not interfere with the same.

10. ABANDONMENT AND RELETTING. If Lessee shall abandon and vacate the Premises,
or if Lessee's right to occupy the Premises be terminated by Lessor by reason of
Lessee's breach of any of the covenants herein, the same may be re-let by Lessor
for such rent and upon such terms as Lessor may deem fit, subject to Illinois
statute; and if a sufficient sum shall not thus be realized monthly, after
paying the expenses of such re-letting and collecting to satisfy the rent hereby
reserved, Lessee agrees to satisfy and pay all deficiency monthly during the
remaining period of this lease.

                                       3
<PAGE>   4
11. HOLDING OVER. Lessee will, at the termination of this lease by lapse of time
or otherwise, yield up immediate possession to Lessor, and failing so to do,
will pay as liquidated damages, for the whole time such possession is withheld
the sum of FIVE HUNDRED AND 00/100 Dollars ($500.00) per day; but the provisions
of this clause shall not be held as a waiver by Lessor of any rights of re-entry
as hereinafter set forth; nor shall the receipt of said rent or any part thereof
or any other act in apparent affirmance of tenancy, operate as a waiver of the
right to forfeit this lease and the term hereby granted for the period still
unexpired, for a breach of any of the covenants herein.

12. EXTRA FIRE HAZARD. There shall not be allowed, kept, or used on the Premises
any inflammable or explosive liquids or materials save such as may be necessary
for use in the business of the Lessee, and in such case, any such substances
shall be delivered and stored in amount, and used, in accordance with the rules
of the applicable Board of Underwriters and statutes and ordinances now or
hereafter in force.

13. DEFAULT BY LESSEE. If default be made in the payment of the above rent, or
any part thereof, which remains uncured for 5 days following Lessee's receipt of
written notice thereof from Lessor, or in any of the covenants herein contained
to be kept by the Lessee which remain uncured 20 days following Lessee's receipt
of written notice thereof from Lessor, Lessor may at any time thereafter at his
election declare said term ended and re-enter the Premises or any part thereof,
with or (to the extent permitted by law) without notice or process of law, and
remove Lessee or any persons occupying the same, without prejudice to any
remedies which might otherwise be used for arrears of rent, and Lessor shall
have at all times the right to distrain for rent due, and shall have a valid and
first lien upon all personal property which Lessee now owns, or may hereafter
acquire or have an interest in, which is by law subject to such distrain, as
security for payment of the rent herein reserved.

14. NO RENT DEDUCTION OR SET OFF. Lessee's covenant to pay rent is and shall be
independent of each and every other covenant of this lease. Lessee agrees that
any claim by Lessee against Lessor shall not be deducted from rent nor set off
against any claim for rent in any action.

15. RENT AFTER NOTICE OR SUIT. It is further agreed, by the parties hereto, that
after the service of notice or the commencement of a suit or after final
judgment for possession of the Premises, Lessor may receive and collect any rent
due, and the payment of said rent shall not waive or affect said notice, said
suit or said judgment.

16. PAYMENT OF COSTS. Lessee will pay and discharge all reasonable costs,
attorney's fees and expenses that shall be made and incurred by Lessor in
enforcing the covenants and agreements of this lease.

17. RIGHT CUMULATIVE. The rights and remedies of Lessor under this lease are
cumulative. The exercise or use of any one or more thereof shall not bar Lessor
from

                                       4
<PAGE>   5

exercise or use of any other right or remedy provided herein or otherwise
provided by law, nor shall exercise nor use of any rights or remedy by Lessor
waive any other right or remedy.

18. FIRE AND CASUALTY. In case the Premises shall be rendered untenantable
during the term of this lease by fire or other casualty, Lessor at this option
may terminate the lease or repair the Premises within 60 days thereafter. If
Lessor elects to repair, this lease shall remain in effect provided such repairs
are completed within said time, and provided that rent for the Premises will be
presented and reduced accordingly for any period in which the Premises are
untenantable. If Lessor shall not have repaired the Premises within said time,
then at the end of such time the term hereby created shall terminate. If this
lease is terminated by reason of fire or casualty as herein specified, rent
shall be apportioned and paid to the day of such fire or casualty.

19. SUBORDINATION. This lease is subordinate to all mortgages which may now or
hereafter affect the Premises.

20. PLURALS; SUCCESSORS. The words "Lessor" and "Lessee" wherever herein
occurring and used shall be construed to mean "Lessors" and "Lessors" in case
more than one person constitutes either party to this lease; and all the
covenants and agreements contained shall be binding upon, and inure to, their
respective successors, heirs, executors, administrators and assigns and may be
exercised by his or their attorney or agent.

21. SEVERABILITY. Wherever possible each provision of this lease shall be
interpreted in such manner as to be effective and valid under applicable law,
but if any provision of this lease shall be prohibited by or invalid under
applicable law, such provision shall be ineffective to the extent of such
prohibition or invalidity, without invalidating the remainder of such provision
or the remaining provisions of this lease.

SEE DIAGRAM, "RIDER A" TO LEASE DATED MAY 6, 1999, AND "RIDER B" TO LEASE DATED
MAY 6, 1999, ALL ATTACHED HERETO AND MADE A PART HEREOF.

         If this instrument is executed by a corporation, such execution has
been authorized by a duly adopted resolution of the Board of Directors of such
corporation.

         This lease consists of five pages numbered 1 to 5, as well at a diagram
of the Premises, a rider, dated May 7, 1999 consisting of two pages, and a rider
dated May 7, 1999, consisting of two pages, all identified by Lessor and Lessee.

                                       5
<PAGE>   6

IN WITNESS WHEREOF, the parties hereto have executed this instrument this day
and year first above written.

UNITED STATES BRASS                         CHICAGO MAP CORPORATION
& COPPER COMPANY

/s/ David Kavanaught      5/10/99          /s/ Steven Peskaitis       5/7/99
-----------------------------------        -------------------------------------
Name                       Date            Name                        Date

President                                  President
-----------------------------------        -------------------------------------
Title                                      Title

                                           /s/ Mike Barnett           5/7/99
-----------------------------------        -------------------------------------
Name                       Date            Name                        Date

                                           Secretary
-----------------------------------        -------------------------------------
Title                                      Title

                                       6
<PAGE>   7

                              ASSIGNMENT BY LESSOR

         On this _______________, 20_____, for value received, Lessor hereby
transfers, assigns and sets over to , all right, title and interest the above,
Lease and the rent thereby received, except rent thus and payable prior to
____________________, 20______.

                                                                          (SEAL)
                                    -------------------------------------

                                                                          (SEAL)
                                    -------------------------------------

                                       7
<PAGE>   8
RIDER A TO LEASE, DATED MAY 7, 1999 BETWEEN UNITED STATES BRASS & COPPER CO., AS
LESSOR, AND CHICAGO MAP CORPORATION, AS LESSEE

1. Lessee shall pay Lessor rent monthly in advance as follows:

                                    Monthly                    Annual
                                    -------                    ------

         Year One                   $7,916.75                $ 95,000.00
         Year Two                   $8,154.25                $ 97,850.00
         Year Three                 $9,398.75                $100,786.00
         Year Four                  $8,650.75                $103,809.00
         Year Five                  $8,910.25                $106,923.00

   Possession of the Premises shall be granted to Lease, May 7, 1999, but no
   rent shall be payable for the period from May 7, 1999 to May 31, 1999.

2. All gas and electric bills for the Premises shall be paid by Lessee, per
   separate meters now being installed for the space occupied by Lessee.

3. All sewer and water charges for the building shall be paid by Lessor and
   Lessee shall reimburse Lessor pro-rate therefor based on area occupied by
   Lessee. Lessee shall reimburse Lessor in the amount of $300.00 a month as its
   share of landscaping charges from spring cleanup through November.

4. Real estate taxes for 1997 are $41,450.62. Tenant shall pay 20% of any
   increase thereof yearly for the period of the Lease.

5. Lessee shall pay up to $1,000.00 per occurrence towards the repair or
   replacement of any individual HVAC units in or servicing the premises. Lessee
   shall pay for the quarterly maintenance contract for the HVAC units in or
   servicing the premises. Lessee shall pay for the quarterly maintenance
   contract for the HVAC units.

6. Forty (40) Parking spaces are included with the Lease, and Lessee shall pay
   all snow removal costs for those spaces. Lessee may use the docks as
   necessary with the Lessor's cooperation. All parking lot repairs, snow
   removal in alleys, driveway to dock and clean-up charges relating to the
   common area shall be paid by Lessor.

7. Lessee shall be allotted approximately 600 sq. ft. of warehouse space at a
   rental of $250.00 per month which will be secured by fencing installed at
   Lessor's expense.

                                       8
<PAGE>   9

8.   Roof structure, parking lot and exterior walls are to be maintained by
     Lessor except for damage caused by Lessee.

9.   Upon execution of this Extension Agreement, Lessee shall deposit $15,000.00
     with Lessor as a security deposit for the faithful performance of all the
     terms and conditions of the Lease Agreement. In no event shall Lessor be
     obligated to apply the deposit on rents or other charges in arrears or on
     damages for failure to perform the terms and conditions of the Lease by
     Lessee.

     The security deposit is to be returned to Lessee when the Lease Agreement
     is terminated, according to the terms of the Lease Agreement, if not
     applied toward the payment of rent in arrears or toward the payment of
     damages suffered by Lessor by result of any breach of the terms and
     conditions of the Lease Agreement by Lessee.

     In no event is the security to be returned until Lessee has vacated the
     demised Premises and delivered possession to the Lessor. The security
     deposit will draw no interest and Lessor shall not be obligated to hold the
     security in a separate fund, but may mix the security with other funds of
     Lessor.

10.  Lessee shall, at is sole cost and expense, obtain and maintain in full
     force and effect for the mutual benefit of the Lessor and Lessee,
     comprehensive public liability insurance in the minimum amount of
     $1,000,000 combined single limit coverage against claims for bodily injury,
     death, or property damage arising out of the use and occupancy of the
     Premises. This insurance shall include public liability insurance against
     claims for bodily injury, death or property damage occurring in or on the
     building, streets, sidewalks, parking and contiguous areas, and the Lessor
     shall be named as an additional insured.

     Whatever (1) any loss, cost, damage or expense resulting from fire
     explosion or any other casualty or occurrences is incurred by either of the
     parties to this Lease Agreement in connection with the demised premises and
     (2) such party is then covered in whole or in party by insurance with
     respect to such loss, cost, damage or expense, then the party so insured
     hereby releases the other party from any liability it may have on account
     of such loss, cost, damage or expense to the extent of any amount recovered
     by reason of such insurance and waives any right of subrogation which might
     otherwise exist in or accrue to any person on account thereof, provided
     that such release of liability and waiver of the right of subrogation shall
     not be operative in any case where the effect thereof is to invalidate such
     insurance

                                       9
<PAGE>   10

     coverage or increase the cost thereof (provided that in the case of the
     increased cost, the other party shall have the right within thirty (30)
     days following written notice, to pay such increased cost, thereupon
     keeping such release and waiver in full force and effect.).

UNITED STATES BRASS                         CHICAGO MAP CORPORATION
& COPPER COMPANY

/s/ David Kavanaught     5/10/99           /s/ Steven Peskaitis       5/7/99
-----------------------------------        -------------------------------------
Name                       Date            Name                        Date

President                                  President
-----------------------------------        -------------------------------------
Title                                      Title

                                           /s/ Mike Barnett            5/7/99
-----------------------------------        -------------------------------------
Name                       Date            Name                        Date

                                           Secretary
-----------------------------------        -------------------------------------
Title                                      Title

                                       10

<PAGE>   11
                           RIDER B TO BUILDING LEASE
        DATED MAY 7, 1999, BETWEEN UNITED STATED BRASS & COPPER CO., AS
                 LESSOR, AND CHICAGO MAP CORPORATION, AS LESSEE

                        AGREEMENT ON FACILITY WORK ORDER

1.   Lessor will paint all office areas except the two executive offices,
     executive conference room, executive waiting area, main conference room and
     lobby, which will have wall covering.

2.   Lessor will put up new wall covering and remove old wall covering in
     areas referenced above.

3.   Lessee will be responsible for the cost of wall covering for the above
     areas, less a painting allowance of $.40/sq. ft.

4.   Lessor will give the Lessee's a carpet allowance of $14/sq. yd. for the
     area of the building that is currently carpeted.

5.   Lessee will carpet all space with the exception of the east wing.

6.   Lessee is responsible for cleaning the carpet in the east wing.

7.   Lessor will provide vinyl molding throughout the offices.

8.   Lessor will re-key all outside entrances and provide keys for interior
     offices.

9.   Lessor will replace tile in washrooms with new ceramic tile, new light
     fixtures and vanities, including counter tops and sinks. Lessor will clean
     doors to washrooms and install kick plates to protect lower portion of
     door. Lessor will paint or repair stalls in bathrooms.

10.  Lessor will clean all ceiling tiles and replace where necessary.

11.  Lessor will clean all air ducts.

12.  Lessor will clean all vertical blinds and repair or replace where
     necessary.

13.  Lessor will refinish reception desk to match existing trim/woodwork and
     make appropriate repairs to executive secretary station.

14.  Lessor will close off south door to employee area and install door or
     warehouse side at north end of same.

                                       11
<PAGE>   12
15.  Lessor will clean and polish stone floor in lobby/foyer.

16.  Lessor will repair and re-hang pocket doors in executive offices.

17.  Lessor will seal and repair all windows throughout the Premises.

18.  Lessor will effect other repairs, as necessary, to deliver the Premises in
     working/aesthetically proper order as identified prior to moving in and up
     to 60 days thereafter.

19.  Lessor will ensure that facilities have been sprayed for insects and
     rodents prior to Lessee's occupation of the Premises.

20.  Lessor will repair the water problem in the east lobby.

21.  Lessor will replace tiles in east lobby entrance.

22.  Lessor will replace tubes in all light fixtures, clean lenses and light
     fixtures.

23.  Lessor will reimburse Lessee for the incremental (versus standard 6'8"
     door) cost of installing 4'6" doors and sidelines in the new private
     offices.

UNITED STATES BRASS                              CHICAGO MAP CORPORATION
& COPPER COMPANY                                 -----------------------
-------------------

/s/ David Kavanaught     5/10/99                 /s/ Steven Peskaitis   5/7/99
----------------------------------               -------------------------------
Name                      Date                   Name                    Date

President                                        President
----------------------------------               -------------------------------
Title                                            Title

                                                 /s/ Mike Barnett       5/7/99
----------------------------------               -------------------------------
Name                      Date                   Name                    Date

                                                 Secretary
----------------------------------               -------------------------------
Title                                            Title

                                       12

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