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                                                                   EXHIBIT 10.13

                                  OFFICE LEASE


                      Fasken Center, Tower Two, Suite 700
                  500 West Texas Avenue, Midland, Texas  79701


This Lease ("Lease") is made as of the 10th day of October, 1996 and between
the Lessor and the Lessee named below.

                         ARTICLE 1 - BASIC LEASE TERMS

For the purposes of this Lease, the following terms shall have the meanings set
forth below:

1.1  Lessor.

         Fasken Center, Ltd. , a Texas limited partnership whose address is
P.O. Box 11227, Midland, Texas 79702.

1.2 Lessee.

         Vista Resources, Inc., whose address is 550 West Texas Avenue, Suite
700 Midland, Texas 79701.

1.3  Manager.

         Haley Properties, Inc., a Texas corporation whose address is P.O. Box
11227, Midland, Texas 79702.

1.4  Building.

         The Building (including the Leased Premises) known as Fasken Center,
500 West Texas Avenue, Midland, Texas 79701, located on the tract of land (the
"Land") described on Exhibit "A" hereto, together with all other buildings,
structures, fixtures and other improvements located thereon from time to time.
The Building and the Land are collectively referred to herein as the
"Property".

1.5  Leased Premises.

         Approximately 6,000 square feet of Net Rentable Area ( as defined in
section 13.3 herein) in the Building as more fully diagrammed on the floor
plans of such premises attached hereto and made a part hereof as Exhibit "B",
on the floor(s) indicated thereon, together with a common area percentage
factor determined by Lessor.  Said demised space represents approximately
1.399610% of the Total Net Rentable Area, such Total Net Rentable Area of the
Building being approximately 421,546 square feet.

1.6  Lease Term.

         Five (5) years and Zero (0)  months, beginning on the Commencement
Date.
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1.7  Commencement Date.

         The Commencement Date shall be September 1, 1997 (the "Commencement
Date").  The Commencement Date shall constitute the commencement of the term of
this Lease for all purposes, whether or not Lessee has actually taken
possession. If this Lease is executed before the Leased Premises become vacant
or otherwise available and ready for occupancy by Lessee, or if any present
occupant of the Leased Premises holds over and Lessor cannot acquire possession
of the Leased Premises before the Commencement Date, then (a) Lessee's
obligation to pay rent hereunder shall be waived until Lessor tenders
possession of the Leased Premises to Lessee, (b) the term shall be extended by
the time between the scheduled Commencement Date and the date on which Lessor
tenders possession of the Leased Premises to Lessee (which date will then be
defined as the Commencement Date), (c) Lessor shall not be in default hereunder
or be liable for damages therefore, and (d) Lessee shall accept possession of
the Leased Premises when Lessor tenders possession thereof to Lessee.

1.8  Base Rent.

         During the term of this Lease, Lessee hereby agrees to pay a Base
Rental (herein called "Base Rental") in the amount set out in Exhibit  "C",
which Exhibit is executed by Lessor and Lessee contemporaneously herewith and
incorporated herein by reference for all purposes.

1.9  Security Deposit.

         Security Deposit is $-0-.

1.10  Permitted Use.

         The Leased Premises are to be used and occupied by Lessee solely for
the purposes of  office space and for no other purpose without Lessor's
expressed written consent.

1.11  Common Areas.

         Such parking areas, streets, driveways, aisles, sidewalks, curbs,
delivery passages, loading areas, lighting facilities, designated elevators,
public corridors, stairwells, lobbies, restrooms, and all other areas situated
on or in the Property which are designated by Lessor from time to time, for use
by all tenants of the Property in common.

1.12  Deleted.

1.13  Operating Expense Base.

         The base calendar year for purposes of calculating Operating Expenses
shall be 1996 and shall be calculated on a per net rentable square foot for the
Property (the "Operating Expense Base").

1.14  Parking.

         Lessor agrees to provide parking in the attached parking garage for
Fourteen (14) Contract parking spaces at the rate of $-0- per space per month.

                ARTICLE 2. - GRANTING CLAUSE AND RENT PROVISIONS

2.1  Grant of Premises.

         In consideration of the obligation of Lessee to pay the rent and other
charges as provided in this Lease, and in consideration of the other terms and
provisions of this Lease, Lessor hereby leases the Leased Premises to Lessee
during the Lease Term, subject to the terms and provisions of this Lease.





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2.2  Base Rent.

         Lessee agrees to pay monthly as base rent during the term of this
Lease the sum of money set forth in Section 1.8 of this Lease, which amount
shall be payable to Lessor at the address shown in Section 1.1 above or at such
address that Lessor in writing shall notify Lessee.  The first  monthly
installment of rent shall be due and payable on the Commencement Date and a
like monthly installment shall be due and payable on or before the first day of
each calendar month succeeding the Commencement Date during the term of this
Lease, without demand offset or reduction;.  Unless otherwise specified, Lessee
shall pay as additional rent all other sums due under this Lease at the same
time and in the same manner as the base rent due hereunder. No payment by
Lessee or receipt by Lessor of a lesser amount than the monthly installment of
rents herein stipulated shall be deemed to be other than a payment on account
of the earliest stipulated rent and/or additional rent; nor shall any
endorsement of payment on any check or any letter accompanying any check or
payment as rent be deemed an accord or satisfaction and Lessor may accept such
check for payment without prejudice to Lessor's right to recover the balance of
such rent and/or additional rent or to pursue any other remedy provided in this
Lease and/or under applicable law.

2.3  Operating Expenses.

         If Lessor's Operating Expenses per net rentable square foot for the
Property, in any calendar year during the term of this Lease exceeds the
Operating Expense Base, Lessee agrees to pay as additional rent Lessee's Share
of Such Excess Operating Expenses.  As used herein, the term "Lessee's Share of
Such Excess Operating Expenses" means the amount by which Lessor's Operating
Expenses per net rentable square foot for the Property exceed the Operating
Expense Base, multiplied by the net rentable square feet comprising the Leased
Premises.  Lessor may invoice Lessee monthly for Lessee's share of the
estimated increase in operating expenses for each calendar year beginning with
calendar year 1997, which amount shall be adjusted each year based upon
anticipated operating expenses.  Within one-hundred twenty (120) days following
the close of each calendar year, Lessor shall provide Lessee an accounting
showing in reasonable detail all computations of additional rent due under this
section.  Failure of Lessor to give Lessee said notice within said time period
shall not be a waiver of Lessor's right to collect said additional rent.  If
the accounting shows that the total of the monthly payments made by Lessee
exceeds the amount of the additional rent due by Lessee under this section, the
accounting shall be accompanied by a refund.  If the accounting shows that the
total of the monthly payments made by Lessee is less than the amount of
additional rent due by Lessee under this section, the accounting shall be
accompanied by an invoice for the additional rent.   Lessee shall have the
right at its own expense and within a reasonable time, to audit during Lessor's
regular business hours Lessor's books relevant to the additional rent payable
under this Section..  Lessee agrees to pay any additional rent due under this
Section within thirty (30) days following receipt of the invoice or accounting
showing additional rent due.

2.4  Definition of Operating Expenses.

         The term "Operating Expenses" includes all expenses incurred by Lessor
with respect to the maintenance, servicing, repairing and operation of the
Property  These expenses shall include maintenance, repair and replacement
costs (other than major or substantive repair, replacement and general
maintenance of the roof, foundation and exterior walls of the Building);
electricity, fuel, water, sewer, gas and other utility charges; security,
window washing and janitorial services; trash and snow and ice removal;
landscaping and pest control; management fees payable to Lessor or third
parties for the management of the Property; wages and salaries of all employees
employed by Manager or Lessor, engaged in the operation, repair, replacement,
maintenance, and security of the Building, including taxes,  insurance, and
benefits relating thereto; all services, supplies, repairs, replacement or
other expenses for maintaining and operating the Property including parking and
common areas; the cost including interest at a rate per annum equal to the
Prime Rate (as defined in Section 11.2 a. hereof), amortized over a reasonable
period, of any capital improvement made to the Property by Lessor after the
date of this Lease which is required under any governmental law or regulation
that was not applicable to the Property at the time it was constructed; the
cost, including interest at the Prime Rate, amortized over a reasonable period,
of installation of any device or other equipment which improves the operating
efficiency of any system applicable to the Leased Premises or the Property and
thereby reduces operating expenses; all other expenses which generally would be
regarded as operating and maintenance expenses which would be reasonably
amortized over a period not to exceed five (5) years; all real property taxes
and installments of special assessments, including dues and assessments by
means of deed restrictions and/or owner's associations which accrue against the
Property during the term of this Lease; governmental levies or charges of any
kind or nature assessed or imposed on the Property, whether by state, county,
city or any political subdivision thereof; and all insurance premiums Lessor is
required to pay or deems necessary to pay including public liability insurance,
with respect to the Property.  The term operating expenses does not include the
following:  expenses for repairs, restoration or other





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work occasioned by fire, wind, the elements or other casualty to the extent
they are covered by insurance proceeds; income and franchise taxes of Lessor or
Manager; expenses incurred in leasing to or procuring of tenants, leasing
commissions, advertising expenses and expenses for the renovating of space for
new or existing tenants; interest or principal payments on any mortgage or
other indebtedness of Lessor; compensation paid to any employee of Lessor above
the grade of property manager; any depreciation allowance or expense; operating
expenses which are the responsibility of Lessee; or that portion of after hours
charges specifically attributable to increased utility costs as calculated by
Lessor.

         Notwithstanding the foregoing, Lessee shall not be charged for any
increases in Operating Expenses, except for the actual increases in
Noncontrollable Expenses (as defined below), of more than one hundred per cent
(100%) of any increase in the Consumer Price Index for Urban Wage Earners
("CPI-U") maintained by the United States Department of Labor, with a base
month of December 1996.  For example, if the CPI-U for December 1996 is 100,
and the CPI-U for December 1997 is 103, then excess Operating Expenses to be
paid to Lessor shall not be greater than three per cent (3%) above the
Operating Expense Base. Notwithstanding the last two sentences, any increases
in the expense of real property and ad valorem taxes, insurance, utilities
(including water and garbage, sewer, electricity, natural gas fuel), third
party contractors (not affiliated in any way with Lessor or Manager) such as
janitorial and mechanical services, and government levies or charges of any
kind or nature assessed or imposed on the Property and directly paid by Lessor,
whether by State, County, City or any political subdivision thereof
(collectively, "Noncontrollable Expenses") shall not be limited to the increase
in the CPI-U as set forth above.

2.5  Late Payment Charge.

         Other remedies for nonpayment of rent notwithstanding, if any monthly
rental payment is not received by Lessor on or before the  tenth (10th) day of
the month for which the rent is due, or if any other payment hereunder due
Lessor by Lessee is not received by Lessor on or before the  tenth (10th) day
of the month next following the month in which Lessee was invoiced, a late
payment charge of ten percent (10%) of such past due amount shall become due
and payable in addition to such amounts owed under this Lease.  Alternatively,
at Lessor's election, all payments required of Lessee hereunder shall bear
interest from the date due until paid at the maximum lawful rate. In no event,
however, shall the charges permitted under this Section 2.5 or elsewhere in
this Lease, to the extent the same are considered to be interest under
applicable law, exceed the maximum lawful rate of interest.

2.6  Increase In Insurance Premiums.

         If an increase in any insurance premiums paid by Lessor for the
Property is caused by Lessee's use of the Leased Premises or if Lessee vacates
the Leased Premises prior to the expiration of the term of this Lease and
causes an increase in such premiums, then Lessee shall pay as additional rent
the amount of such increase to Lessor and acceptance of such payment shall not
constitute  waiver of any of Lessor's other rights.  Lessee agrees to pay any
amount due under this Section within ten (10) days following receipt of the
invoice showing the additional rent due.

2.7  Deleted.

2.8  Holding Over.

         If Lessee does not vacate the Leased Premises upon the expiration or
earlier termination of this Lease, Lessee shall be a tenant at will for the
holdover period and all of the terms and provisions of this Lease shall be
applicable during that period, except that Lessee shall pay Lessor (in addition
to additional rent payable under Section 2.3 and any other sums payable under
this Lease) as base rental for the period of such holdover an amount equal to
two times the base rent which would have been payable by Lessee had the
holdover period been a part of the original term of this Lease (without waiver
of Lessor's right to recover damages as permitted by law). Upon the expiration
or earlier termination of this Lease, Lessee agrees to vacate and deliver the
Leased Premises, and all keys thereto, to Lessor upon delivery to Lessee of
notice from Lessor to vacate.  The rental payable during the holdover period
shall be payable to Lessor on demand.  No holding over by Lessee, whether with
or without the consent of Lessor, shall operate to extend the term of this
Lease.  Lessee shall indemnify Lessor against all claims made by any tenant or
prospective tenant against Lessor resulting from delay by Lessor in delivering
possession of the Leased Premises to such other tenant or prospective tenant.

2.9  Parking.





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         The parking spaces set forth in Section 1.14 shall be for Lessee
and/or Lessee's employees and Lessor shall have the right to assign parking
space as conditions permit. However, Lessor shall not be required to police the
use of these spaces.  Lessor may make, modify and enforce reasonable rules and
regulations relating to the parking of automobiles in the parking area(s), and
Lessee shall abide  thereby.  Lessor shall not be liable to Lessee or Lessee's
agents, servants, employees, customers, or invitees for damage to person or
property caused by any act omission or neglect of Lessee, and Lessee agrees to
hold Lessor harmless from all claims for any such damage.

                   ARTICLE 3. - OCCUPANCY, USE AND OPERATIONS

3.1  Use.

         Lessee warrants and represents to Lessor that the Leased Premises
shall be used and occupied only for the purpose as set forth in Section 1.10.
Lessee shall occupy the Leased Premises, conduct its business and use all
reasonable commercial efforts to control its agents, employees, invitees,
licensees and visitors in such a manner as is lawful, reputable and will not
create a nuisance to other tenants in the Property. Lessee shall not solicit
business, distribute handbills or display merchandise within the Common Areas,
or take any action which would interfere with the rights of other persons to
use the Common Areas.  Lessee shall not permit any operation which emits any
odor or matter which intrudes into other portions of the Property, use any
apparatus or machine which makes undue noise or causes vibration in any portion
of the Property or otherwise interfere with, annoy or disturb any other tenant
in its normal business operations or Lessor in its management of the Property.
Lessee shall neither permit any waste on the Leased Premises nor allow the
Leased Premises to be used in any way which would, in the opinion of Lessor, be
extra hazardous on account of fire or which would in any way increase or render
void the fire insurance on the Property, or permit the storage of any hazardous
materials or substances.

3.2  Signs.

         No signs of any type or description shall be erected, placed or
painted in or about the Leased Premises except those signs submitted to Lessor
in writing and approved (which approval shall not be unreasonably withheld)  by
Lessor in writing, and which signs are in conformity with Lessor's sign
criteria established for the Property.  Lessor reserves the right to remove, at
Lessee's expense, all signs other than signs approved in writing by Lessor
under this Section 3.2 without notice to Lessee and without liability to Lessee
for any damages sustained by Lessee as a result thereof.

3.3  Compliance with Laws, Rules and Regulations.

         Lessee, at Lessee's sole cost and expense, shall comply with all laws,
ordinances, orders rules and regulations of state, federal, municipal or other
agencies or bodies having jurisdiction over the use, condition or occupancy of
the Leased Premises. Lessee shall procure at its own expense all permits and
licenses, if any,  required for the transaction of its business in the Leased
Premises.  Lessee will comply with the rules and regulations of the Property
adopted by Lessor which are set forth on a schedule attached to this Lease.  If
Lessee is not complying with such rules and regulations, or if Lessee is in any
way not complying with this Article 3, then notwithstanding anything to the
contrary contained herein, Lessor, may, at its election and after notice to
Lessee and a reasonable opportunity to correct the non-compliance, enter the
Leased Premises without liability therefor and fulfill Lessee's obligations.
Lessee shall reimburse Lessor on demand for any expenses which Lessor may incur
in effecting compliance with Lessee's obligations and agrees that Lessor shall
not be liable for any damages resulting to Lessee from such action. Lessor
shall have the right at all times to change and amend the rules and regulations
in any reasonable manner as it may deem advisable for the safety, care,
cleanliness, preservation of good order and operation or use of the Property or
the Leased Premises. All changes and amendments to the rules and regulations of
the Property will be forwarded by Lessor to Lessee in writing and shall
thereafter be carried out and observed by Lessee.

3.4 Compliance with all Environmental Laws, Regulations, Policies, Orders, etc.

         Lessee agrees that it will comply fully and promptly with any and all
environmental laws, regulations, statutes, ordinances, policies and orders
issued by any federal, state, county or local governmental authority; that it
will obtain, maintain in full force and effect, and strictly comply with any
and all governmental permits, approvals and authorizations necessary for the
conduct of its business operations; that it will supply Lessor with copies of
any such permits, approvals and authorizations; that it will promptly notify
Lessor of the expiration or revocation of any such permits, approvals and
authorizations; and that it will promptly notify Lessor and supply Lessor with
a copy of any notice of violation of any environmental law, regulation,
statute, ordinance, policy or order





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Lessee receives.

3.5  Quiet Enjoyment.

         Provided Lessee has performed all of the terms and conditions of this
Lease to be performed by Lessee, Lessee shall peaceably and quietly hold and
enjoy the Leased Premises for the term, without hindrance from Lessor or any
party claiming by, through, or under Lessor, subject to the terms and
conditions of this Lease and subject to all mortgages, deeds of trust, leases
and agreements to which this Lease is subordinate and to all laws, ordinances,
orders, rules and regulations of any governmental authority.  Lessor shall not
be responsible for the acts or omissions of any other lessee or third party
that may interfere with Lessee's use and enjoyment of the Leased Premises,
however, Lessor shall use all reasonable commercial efforts to cause other
lessees and third parties that use the Property to comply with the rules and
regulations governing the use of the Property.

3.6  Acceptance of Premises.

         By occupying the Leased Premises, Lessee shall be deemed to have
accepted the Leased Premises in their condition as of the date of such
occupancy subject to completion of punch-list items.  Lessee shall execute and
deliver to Lessor, within ten (10) days after Lessor has requested same, a
letter confirming (i) the Commencement Date, (ii) that Lessee has accepted the
Leased Premises, and (iii) that Lessor has performed all of its obligations
with respect to the Leased Premises (except for punch-list items specified in
such letter) if applicable.

3.7  Inspection.

         Lessor or its authorized agents shall at any and all reasonable times
have the right to enter the Leased Premises to inspect the same, to supply
janitorial service or any other service to be provided by Lessor, to show the
Leased Premises to prospective mortgagees, purchasers or prospective tenants,
and to alter, improve or repair the Leased Premises or any other portion of the
Property.  Lessee hereby waives any claim for abatement or reduction of rent or
for any damages for injury or inconvenience to or interference with Lessee's
business, for any loss of occupancy or use of the Leased Premises, and for any
other loss occasioned thereby.  Lessor shall at all times have and retain a key
with which to unlock all of the doors in, upon and about the Leased Premises.
Lessee shall not change Lessor's lock system or in any other manner prohibit
Lessor from entering the Leased Premises.  Lessor shall have the right at all
times to enter the Leased Premises by any means in the event of an emergency
without liability therefor.

3.8  Security.

         Lessor may, at its option, provide a security service or electronic
security devices to supervise access to the Building during the weekends and
after normal working hours during the week; provided, however, Lessor shall
have no responsibility to prevent, and shall be indemnified by Lessee against
liability to Lessee, its agents, employees, licensees  and invitees for losses
due to theft or burglary, or damages done by persons gaining access to the
Leased Premises or the Building and the parking areas.

3.9  Personal Property Taxes.

         Lessee shall be liable for all taxes levied against leasehold
improvements, merchandise, personal property, trade fixtures and all other
taxable property located in the Leased Premises.  If any such taxes for which
Lessee is liable are levied against Lessor or Lessor's property and if Lessor
elects to pay the same or if the assessed value of Lessor's property is
increased by inclusion of personal property and trade fixtures placed by Lessee
in the Leased Premises and Lessor elects to pay the taxes based on such
increase, Lessee shall pay to Lessor, upon demand, that part of such taxes for
which the Lessee is primarily liable pursuant to the terms of this Section.
Lessee shall pay when due any and all taxes related to Lessee's use and
operation of its business in the Leased Premises.

                       ARTICLE 4. - UTILITIES AND SERVICE

4.1  Building Services.





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         Lessor shall provide water and electricity for Lessee during the term
of this Lease.  Lessee shall pay all telephone charges. Lessor shall furnish
Lessee water at those points of supply provided for general use by other
tenants in the Building, and central heating and air conditioning in season on
business days during regular hours as are considered normal in Midland, Texas
(7:00 a.m. to 6:00 p.m., Monday through Friday, 8:00 a.m. to 1:00 p.m. Saturday
except for legal holidays) and at temperatures and in amounts as are considered
by Lessor to be standard or in compliance with any governmental regulations,
such service at times other than regular hours to be furnished upon request
with not less than twenty-four (24) hours advance notice from Lessee, who shall
bear the entire cost thereof (which cost shall include but not be limited to an
amount that will fairly compensate Lessor for additional services, depreciation
and replacement of capital items and any other costs attributable thereto) at
the rate established by Lessor  which shall not exceed $20.00 per hour.
Lessor shall also provide routine maintenance, painting and electric lighting
service for all public areas and special service areas of the Property in the
manner and to the extent deemed by Lessor to be standard.  Lessor may, in its
sole discretion, provide additional services not enumerated herein.  Failure by
Lessor to any extent to provide these defined services or any other services
not enumerated, or any cessation thereof, shall not render Lessor liable in any
respect for damages to either person or property, be construed as an eviction
of Lessee, work an  abatement of rent or relieve Lessee from fulfillment of any
covenant in this Lease.  If any of the equipment or machinery useful or
necessary for provision of utility services, and for which Lessor is
responsible, breaks down, or for any cause ceases to function properly, Lessor
shall use reasonable diligence to  repair the same promptly, but Lessee shall
have no claim for rebate of rent or damages on account of any interruption in
service occasioned from the repairs.  Lessor reserves the right from time to
time to make changes in the utilities and services provided by Lessor to the
Property.

4.2  Deleted.

4.3  Janitorial Service.

         Lessor shall furnish janitorial services to the Leased Premises and
public areas of the Building five (5) times per week during the term of this
Lease, excluding holidays.  Lessor shall not provide janitorial service to
kitchens or storage areas included in the Leased Premises.

4.4  Excessive Utility Consumption.

         Lessee shall pay all utility costs occasioned by the use of equipment
of high electrical consumption over and above normal PC based computer systems
including (without limitation) the cost of installing, servicing and
maintaining any special or additional inside or outside wiring or lines, meters
or submeters, transformers, poles, air conditioning costs, or the cost of any
other equipment necessary to increase the amount or type of electricity or
power available to the Leased Premises.

4.5  Window Coverings.

         Lessor may (but shall not be obligated to) furnish and install window
coverings on all exterior windows to maintain a uniform exterior appearance.
Lessee shall not remove or replace these window coverings or install any other
window covering which would affect the exterior appearance of the Building.
Lessee may install lined or unlined draperies on the interior sides of the
Lessor furnished window coverings for interior appearance or to reduce light
transmission, provided such over draperies do not (in Lessor's determination)
affect the exterior appearance of the Building or affect the operation of the
Building's heating, ventilating and air conditioning systems.

4.6  Restoration of Services; Abatement.

         Lessor shall use reasonable efforts to restore any service that
becomes unavailable; however, such unavailability shall not render Lessor
liable for any damages caused thereby, be a constructive eviction of Lessee,
constitute a breach of any implied warranty, or, except as provided in the next
sentence, entitle Lessee to any abatement of Lessee's obligations hereunder.
However, if Lessee is prevented from making reasonable use of the Leased
Premises for more than forty-five (45) consecutive days because of the
unavailability of any such service, Lessee shall, as its exclusive remedy
therefor, be entitled to a reasonable abatement of rent for each consecutive
day (after such forty-five (45) day period) that Lessee is so prevented from
making reasonable use of the Leased Premises.

4.7  Deleted.





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                      ARTICLE 5. - REPAIRS AND MAINTENANCE

5.1  Lessor Repairs.

         Unless otherwise expressly stipulated herein, Lessor shall not be
required to make any improvements to or repairs of any kind or character on the
Leased Premises during the term of this Lease, except such repairs as may be
for normal maintenance of the Common Areas which shall include the painting of
and repairs to walls, floors, corridors, windows, and other structures and
equipment within the Common Areas only, and such additional maintenance of the
Common Areas as may be necessary because of damages by persons other than
Lessee, its agents, employees, invitees, licensees or visitors.  Lessor shall
have no obligation to maintain or repair the Leased Premises except as set
forth herein.  Lessor shall replace any and all burned-out or otherwise
non-functioning lighting bulbs, tubes or fixtures located on the Leased
Premises and which are considered fixtures of the Building.  Lessor shall also
be responsible for maintenance and repair of all electrical (including heating
and cooling systems) and plumbing systems necessary to furnish those services
to the Leased Premises.   Lessee will promptly give Lessor notice of any damage
in the Leased Premises requiring repairs by Lessor.  If the Building or the
equipment used to provide the services referred to in Section 4.1 are damaged
by acts or omissions of Lessee, its agents, customers, employees, licensees or
invitees, then Lessee will bear the cost of such repairs. Lessor shall not be
liable to Lessee, except as expressly provided in this Lease, for any damage or
inconvenience, and Lessee shall not be entitled to any damages nor to any
abatement or reduction of rent by reason of any repairs, alterations or
additions made by Lessor under this Lease.  Lessor's cost of maintaining and
repairing the items set forth in this section, including the replacement of
lighting bulbs and tubes,  are subject to the operating expense provisions in
Section 2.3.  All requests for repairs or maintenance that are the
responsibility of Lessor pursuant to any provision of this Lease must be made
by phone and confirmed   in writing to Lessor and Manager at the addresses in
Sections 1.1 and 1.3.

5.2  Lessee Repairs and Damages.

         Lessee, at its own cost and expense, shall maintain the Leased
Premises in a good condition, ordinary wear and tear excepted,  (except for
those items that are the responsibility of Lessor under Section 5.1) and shall
repair or replace any damage or injury to all or any part of the Leased
Premises and/or the Property, caused by any act or omission of Lessee or
Lessee's agents, employees, invitees, licensees or visitors.  Lessee shall not
allow any damage to be committed on any portion of the Leased Premises or
Property, and at the termination of this Lease, by lapse of time or otherwise,
Lessee shall deliver the Leased Premises to Lessor in as good a condition as
existed at the Commencement Date of this Lease, ordinary wear and tear
excepted.  The cost and expense of any repairs necessary to restore the
condition of the Leased Premises shall be borne by Lessee.

                   ARTICLE 6. - ALTERATIONS AND IMPROVEMENTS

6.1  Construction.

         The parties hereto have agreed to certain construction of improvements
on the Leased Premises prior to Lessee's occupation thereof, all as more
particularly set out in Exhibits B and D (the "Leasehold Improvements
Agreement") hereof.  Except as expressly provided in this Lease or in the
Leasehold Improvements Agreement (if any), Lessee acknowledges and agrees that
Lessor has not undertaken to perform any modification, alteration or
improvements to the Leased Premises, and Lessee further waives any defects in
the Leased Premises (except in accordance with Section 6.2 below) and upon the
completion of the build-out  contemplated under the Leasehold Improvements
Agreement, Lessee acknowledges and accepts (1) the Leased Premises as suitable
for the purpose for which they are leased and (2) the Property and every part
and appurtenance thereof as being in good and satisfactory condition.  Upon the
request of Lessor, Lessee shall deliver to Lessor a completed acceptance of
premises memorandum in Lessor's standard form.

6.2  Lessee Improvements.

         Lessee shall not make or allow to be made any material alterations,
physical additions or improvements in or to the Leased Premises without first
obtaining the written consent of Lessor, which consent  shall not be
unreasonably withheld  .  Any alterations, physical additions or improvements
to the Leased Premises made by or installed by either party hereto shall remain
upon and be surrendered with the Leased Premises and become the property of
Lessor upon the expiration or earlier termination of this Lease





                                       8

<PAGE>   9
without credit to Lessee; provided, however, Lessor, at its option, may require
Lessee to remove any physical improvements or additions and/or repair any
alterations in order to restore the Leased Premises to the condition existing
at the time Lessee took possession, all costs of removal and/or alterations to
be borne by Lessee.  This clause shall not apply to moveable equipment,
furniture or moveable trade fixtures owned by Lessee, which may be removed by
Lessee at the end of the term of this Lease if Lessee is not then in default
and if such equipment and furniture are not then subject to any other rights,
liens and interests of Lessor.  Lessee shall have no authority or power,
express or implied, to create or cause any mechanic's or materialmen's lien,
charge or encumbrance of any kind against the Leased Premises, the Property or
any portion thereof.  Lessee shall promptly cause any such liens that have
arisen by reason of any work claimed to have been undertaken by or through
Lessee to be released by payment, bonding or otherwise within thirty (30) days
after request by Lessor, and shall indemnify Lessor against losses arising out
of any such claim (including, without limitation, legal fees and court costs).
If Lessee fails to timely take either such action, then Lessor may pay the lien
claim without inquiry as to the validity thereof, and any amounts so paid,
including expenses and interest, shall be paid by Lessee to Lessor within ten
(10) days after Lessor has delivered to Lessee an invoice therefor.

6.3  Common and Service Area Alterations.

         Lessor shall have the right to decorate and to make repairs,
alterations, additions, changes or improvements, whether structural or
otherwise, in, about or on the Property or any part thereof, and to change,
alter, relocate, remove or replace service areas and/or Common Areas, to place,
inspect, repair and replace in the Leased Premises (below floors, above
ceilings or next to columns) utility lines, pipes and the like to serve other
areas of the Property outside the Leased Premises and to otherwise alter or
modify the Property, and for such purposes to enter upon the Leased Premises
and, during the continuance of any such work, to take such measures for safety
or for the expediting of such work as may be required, in Lessor's judgment,
all without affecting any of Lessee's obligations hereunder.

           ARTICLE 7. - CASUALTY; WAIVERS; SUBROGATION AND INDEMNITY

7.1  Repair Estimate.

         If the Leased Premises or the Building are damaged by fire or other
casualty (a "Casualty"), Lessor shall, within forty-five (45) days after such
Casualty, deliver to Lessee a good faith estimate (the "Damage Notice") of the
time needed to repair the damage caused by such Casualty.

7.2  Lessor's and Lessee's Rights.

         If a material portion of the Leased Premises or the Building is
damaged by Casualty such that Lessee is prevented from conducting its business
in the Leased Premises in a manner reasonably comparable to that conducted
immediately before such Casualty and Lessor estimates that the damage caused
thereby cannot be repaired within  120 days after the commencement of repair,
then Lessor may, at its expense, relocate Lessee to office space reasonably
comparable to the Leased Premises, provided that Lessor notifies Lessee of its
intention to do so in the Damage Notice.  Such relocation may be for a portion
of the remaining term or the entire term.  Lessor shall complete any such
relocation within  120  days after Lessor has delivered the Damage Notice to
Lessee.  If Lessor does not elect to relocate Lessee following such Casualty,
then Lessee may terminate this Lease by delivering written notice to Lessor of
its election to terminate within thirty (30) days after the Damage Notice has
been delivered to Lessee.  If Lessor does not relocate Lessee and Lessee does
not terminate this Lease, then (subject to Lessor's rights under Section 7.3)
Lessor shall repair the Building or the Leased Premises, as the case may be, as
provided below, and Basic Rental for the portion of the Leased Premises
rendered untenantable by the damage shall be abated on a reasonable basis from
the date of damage until the completion of the repair, unless Lessee caused
such damage, in which case, Lessee shall continue to pay rent without
abatement.

7.3  Lessor's Rights.

         If a Casualty damages a material portion of the Building, and Lessor
makes a good faith determination that restoring the Leased Premises would be
uneconomical, or if Lessor is required to pay any insurance proceeds arising
out of the Casualty to Lessor's Mortgagee, then Lessor may terminate this Lease
by giving written notice of its election to terminate within thirty (30) days
after the  Damage Notice has been  delivered to  Lessee, and Basic Rental
hereunder shall be abated as of the date of the Casualty.





                                       9

<PAGE>   10

7.4  Repair Obligation.

         If neither party elects to terminate this Lease following a Casualty,
then Lessor shall, within a reasonable time after such Casualty, commence to
repair the Building and the Leased Premises and shall proceed with reasonable
diligence to restore the Building and Leased Premises to substantially the same
condition as they existed immediately before such Casualty; however, Lessor
shall not be required to repair or replace any part of the furniture,
equipment, fixtures, and other improvements which may have been placed by, or
at the request of, Lessee or other occupants in the Building or the Leased
Premises, and the Lessor's obligation to repair or restore the Building or
Leased Premises shall be limited to the extent of the insurance proceeds
actually received by Lessor for the Casualty in question.

7.5  Property Insurance.

         Lessor shall at all times during the term of this Lease insure the
Property against all risk of direct physical loss in an amount and with such
deductibles as Lessor considers appropriate; provided, Lessor shall not be
obligated in any way or manner to insure any personal property (including, but
not limited to, any furniture, machinery, goods or supplies) of Lessee upon or
within the Leased Premises, any fixtures installed or paid for by Lessee upon
or within the Leased Premises, or any improvements which Lessee may construct
on the Leased Premises.  Lessee shall have no right in or claim to the proceeds
of any policy of insurance maintained by Lessor even if the cost of such
insurance is borne by Lessee as set forth in Article 2.  Lessee at all times
during the term of the Lease shall, at its own expense, keep in full force and
effect insurance against fire and such other risks as are from time to time
included in standard all-risk insurance (including coverage against vandalism
and malicious mischief) for the full insurable value of Lessee's trade
fixtures, furniture, supplies and all items of personal property of Lessee
located on or within the Leased Premises.

7.6  Waiver; No Subrogation.

         Lessor shall not be liable to Lessee or those claiming by, through, or
under Lessee or to Lessee's agents, employees, invitees or licensees for any
injury to or death of any person or persons or the damage to or theft,
destruction, loss, or loss of use of any property (a "Loss") caused by
casualty, theft, fire, third parties, or any other matter beyond the control of
Lessor, or for any injury or damage or inconvenience which may arise through
repair or alteration of any part of the Building, or failure to make repairs,
or from any other cause, except if such Loss is caused by Lessor's gross
negligence or willful misconduct.  Lessor and Lessee each waives any claim it
might have against the other for any damage to or theft, destruction, loss, or
loss of use of any property, to the extent the same is insured against under
any insurance policy that covers the Building, the Leased Premises, Lessor's or
Lessee's fixtures, personal property, leasehold improvements, or business, or
is required to be insured against under the terms hereof, regardless of whether
the negligence or fault of the other party caused such loss.  Each party shall
cause its insurance carrier to endorse all applicable policies waiving the
carrier's rights of recovery under subrogation or otherwise against the other
party.

7.7  Deleted.

7.8  Insurance.

         Lessee shall at its expense procure and maintain throughout the term
of this Lease a general liability insurance policy in an amount of not less
than $500,000.  Lessee shall cause Lessor's name to be added as an additional
insured on such general liability policy which shall insure Lessor against
liability for injury to or death of a person or persons or damage to property
arising from the use and occupancy of the Leased Premises.  Lessee shall
furnish and maintain a current certificate of insurance with Lessor evidencing
the coverage maintained and that Lessor is named as an additional insured
thereunder as it respects the Leased Premises.

7.9 Ad Valorem Taxes.

         Lessee hereby waives any right it may have to contest the appraised
value of the Property or Building as the appraised value may be determined by
any taxing authority.





                                       10

<PAGE>   11
                           ARTICLE 8. - CONDEMNATION

8.1  Taking - Lessor's and Lessee's Rights.

         If any part of the Building is taken by right of eminent domain or
conveyed in lieu thereof (a "Taking"), and such Taking prevents Lessee from
conducting its business in the Leased Premises in a manner reasonably
comparable to that conducted immediately before such Taking, then Lessor may
terminate this Lease.

8.2  Taking - Lessor's Rights.

         If any material portion, but less than all, of the Building becomes
subject to a Taking, or if Lessor is required to pay any of the proceeds
received for a Taking to Lessor's Mortgagee, then this Lease, at the option of
Lessor, exercised by written notice to Lessee within thirty (30) days after
such Taking, shall terminate and rent shall be apportioned as of the date of
such Taking.  If Lessor does not so terminate this Lease, then this Lease will
continue, but if any portion of the Leased Premises has been taken, Base Rental
shall abate as provided in the last sentence of Section 8.1.

8.3  Award.

         If any Taking occurs, then Lessor shall receive the entire award or
other compensation for the Land, the Building, and other improvements taken,
and Lessee may separately pursue a claim against the condemnor for the value of
Lessee's personal property which Lessee is entitled to remove under this Lease,
moving costs, loss of business, and other claims it may have.

         ARTICLE 9. - ASSIGNMENT OR SUBLEASE; SUBORDINATION AND NOTICE

9.1  Sublease; Consent.

         Lessee shall not, without the prior written consent of Lessor (which
Lessor may grant or deny in its sole discretion), (i) advertise that any
portion of the Leased Premises is available for lease, (ii) assign, sublease,
or encumber this Lease or any estate or interest herein, whether directly or by
operation of law,  (iii) sublet any portion of the Leased Premises, (iv) grant
any license, concession, or other right of occupancy of any portion of the
Leased Premises, or (v) permit the use of the Leased Premises by any parties
other than Lessee (any of the events listed in clauses (ii) through (v) being a
"Sublease").  If Lessee requests Lessor's consent to a Sublease, then Lessee
shall provide Lessor with a written description of all terms and conditions of
the proposed Sublease, copies of the proposed documentation, and the following
information about the proposed sublease:  name and address; reasonably
satisfactory information about its business and business history; its proposed
use of the Leased Premises; banking, financial, and other credit information;
and general references sufficient to enable Lessor to determine the proposed
sublessee's credit worthiness and character.  Lessee shall reimburse Lessor for
reasonable  attorneys' fees and other reasonable expenses incurred in
connection with considering any request for its consent to a Sublease.  If
Lessor consents to a proposed Sublease, then the proposed sublessee shall
deliver to Lessor a written agreement whereby it expressly assumes the Lessee's
obligations hereunder; however, any sublessee of less than all of the space in
the Leased Premises shall be liable only for obligations under this Lease that
are properly allocable to the space subject to the Sublease, and only to the
extent of the rent it has agreed to pay Lessee therefor.   Upon the approval by
Lessor of any such Sublease of all of the Leased Premises to a third party
unaffiliated with Lessee and the actual subletting thereof by Lessee, Lessee
shall be released of all liability and obligations under this Lease for
obligations arising or due subsequent to the effective date of such Sublease
for any act, occurrence or omission relating to the Leased Premises or this
Lease.  Lessor's consent to any Sublease shall not waive Lessor's rights as to
any subsequent Subleases.  If an Event of Default occurs while the Leased
Premises or any part thereof are subject to a Sublease, then Lessor, in
addition to its other remedies, may collect directly from such sublessee all
rents becoming due to Lessee and apply such rents against rent.  Lessee
authorizes its sublessees to make payments of rent directly to Lessor upon
receipt of notice from Lessor to do so.  To the extent that any such Sublease
may provide for rents in excess of the rental rate then in effect for the
Leased Premises, then Lessee and Lessor shall divide and share such excess
rental on a 50 - 50 basis.

9.2  Deleted.





                                       11

<PAGE>   12
9.3  Deleted.

9.4  Lessor Assignment.

         Lessor shall have the right to sell, transfer or assign, in whole or
in part, its rights and obligations under this Lease and in the Property.  Any
such sale, sublease or assignment shall operate to release Lessor from any and
all liabilities under this Lease arising after the date of such sale,
assignment or transfer; provided that the acquirer thereof expressly assumes in
writing the obligations of Lessor under this Lease.

9.5  Rights of Mortgagee.

         Lessee accepts this Lease subject and subordinate to any recorded
lease, mortgage or deed of trust lien presently existing, if any, or hereafter
encumbering the Property and to all existing ordinances and recorded
restrictions, covenants, easements, and agreements with respect to the
Property, Lessor hereby is irrevocably vested with full power and authority to
subordinate Lessee's interest under this Lease to any mortgage or deed of trust
lien hereafter placed on the Property.  Upon any foreclosure, judicially or
non-judicially, of any such mortgage, or the sale of the Property in lieu of
foreclosure, or any other transfer of Lessor's interest in the Property,
whether or not in connection with a mortgage, Lessee hereby does, and hereafter
agrees to attorn to the purchaser at such foreclosure sale or to the grantee
under any deed in lieu of foreclosure or to any other transferee of Lessor's
interest, and shall recognize such purchaser, grantee, or other transferee as
Lessor under this Lease, and no further attornment or other agreement shall be
required to effect or evidence Lessee's attornment to and recognition of such
purchaser or grantee as Lessor hereunder.  Such agreement of Lessee to attorn
shall survive any such foreclosure sale, trustee's sale, conveyance in lieu
thereof, or any other transfer of Lessor's interest in the Property.  Lessee,
upon demand, at any time, before or after any such foreclosure sale, trustee's
sale, conveyance in lieu thereof, or other transfer shall execute, acknowledge,
and deliver to the prospective transferee and/or mortgagee the Lease
Subordination, Non-disturbance and Attornment Agreement and any additional
written instruments and certificates evidencing such attornment as the
mortgagee or other prospective transferee may reasonably require, and Lessee
hereby irrevocably appoints Lessor as Lessee's agent and attorney-in-fact for
the purpose of executing, acknowledging, and delivering any such instruments
and certificates.  Notwithstanding anything to the contrary implied in this
Section, any mortgagee under any mortgage shall have the right at any time to
subordinate any such mortgage to this Lease on such terms and subject to such
conditions as the mortgagee in its discretion may consider appropriate.   Any
actions or instruments executed by Lessee shall be conditioned upon the
mortgagee or transferee executing a letter of non-disturbance reasonably
satisfactory in form and substance to Lessee.  Any instrument executed by
Lessee under this Section shall not in any manner limit the rights and
privileges granted to Lessee in this Lease, nor shall it relieve Lessor's
successors in interest (including mortgagees) of any of Lessor's obligations
and duties under this Lease.

9.6  Mortgagee's Right to Cure.

         No act or omission by Lessor which would entitle Lessee under the
terms of this Lease or any Laws to be relieved of Lessee's obligations
hereunder, or to terminate this Lease, shall result in a release or termination
of such obligations or this Lease unless: (a)Lessee first shall have given
written notice of Lessor's act or omission to Lessor and all Lessor's
Mortgagees whose names and addresses shall have been furnished to Lessee; and
(b) Lessor's Mortgagees, after receipt of such notice, fail to correct or cure
the act or omission within a reasonable time thereafter (but in no event less
than  forty-five (45) days). However, nothing contained in this Section shall
impose any obligation on Lessor's Mortgagees to correct or cure any act or
omission.

9.7  Estoppel Certificates.

         Lessee agrees to furnish, from time to time, within ten (10) days
after receipt of a request from Lessor's or Lessor's Mortgagee, a statement
certifying, if applicable, all of the following:  Lessee is in possession of
the Leased Premises; the Lease is in full force and effect; the Lease is
unmodified (except as disclosed in such statement); Lessee claims no present
charge, lien, or claim of offset against rent; the rent is paid for the current
month, but is not prepaid for more than one (1) month and will not be prepaid
for more than one (1) month in advance; there is no existing default by reason
of some act or omission by Lessor; that Lessor has performed all inducements
required of Lessor, in connection with this Lease, including construction
obligations, and Lessee accepts the Leased Premises as constructed; an
acknowledgment of the assignment of rentals and other sums due hereunder to the
mortgage and agreement to be bound thereby; an agreement requiring Lessee to
advise the mortgagee of damage to or destruction of the Leased Premises by fire
or other casualty requiring reconstruction; an agreement by Lessee to give the
mortgagee written notice of Lessor's default hereunder and to permit mortgagee
to cure such default within no less than  forty-five (45) days after such
notice before exercising any remedy Lessee might possess as a result of such
default; and such other matters





                                       12

<PAGE>   13
as may be reasonably required by Lessor or Lessor's Mortgagee. Lessee's failure
to deliver such statement, in addition to being a default under this Lease,
shall be deemed to establish conclusively that this Lease is in full force and
effect except as declared by Lessor, that Lessor is not in default of any of
its obligations under this Lease, and that Lessor has not received more than
one (1) month's rent in advance.

                              ARTICLE 10. - LIENS

10.1  Deleted.

                       ARTICLE 11. - DEFAULT AND REMEDIES

11.1  Events of Default.

         Each of the following occurrences shall constitute an "Event of
Default":

         a.   Lessee's failure to pay rent, or any other sums due from Lessee
to Lessor under the Lease (or any other lease executed by Lessee for space in
the Building), after ten (10) days written notice of Lessor's claim being sent
to Lessee;

         b.   Lessee's failure to perform, comply with, or observe any other
agreement or obligation of Lessee under this Lease (or any other Lease executed
by Lessee for space in the Building} within thirty (30) days after written
notice is given to Lessee setting forth the specific failure to comply as
claimed by Lessor and provided Lessee does not correct or otherwise cure such
failure within such thirty (30) day time period ;

         c.   Deleted.

         d.   Deleted.

         e.   Deleted.

         f.   Lessee's death, dissolution or termination of existence.


11.2  Remedies.

         Upon any Event of Default, Lessor may, in addition to all other rights
and remedies afforded Lessor hereunder or by law or equity, take any of the
following actions:

         a.   Terminate this Lease by giving Lessee written notice thereof, in
which event, Lessee shall pay to Lessor the sum of (i) all rent accrued
hereunder through the date of termination, (ii) all amounts due under Section
11.3., and (iii) an amount equal to (A) the total rent that Lessee would have
been required to pay for the remainder of the term discounted to present value
at a per annum rate equal to the "Prime Rate" as published (on the date this
Lease is terminated) by The Wall Street Journal, Southwest Edition, in its
listing of "Money Rates", minus (B) the then present fair rental value of the
Leased Premises for such period, similarly discounted; or

         b.   Terminate Lessee's right to possession of the Leased Premises
without terminating this Lease by giving written notice thereof to Lessee, in
which event Lessee shall pay to Lessor (i) all rent and other amounts accrued
hereunder to the date of termination of possession, (ii) all amounts due from
time to time under Section 11.3., and (iii) all rent and other sums required





                                       13

<PAGE>   14
hereunder to be paid by Lessee during the remainder of the term, reduced by any
net sums thereafter received by Lessor through reletting the Leased Premises
during such period.  Lessor shall use reasonable efforts to relet the Leased
Premises on such terms and conditions as Lessor in its sole discretion may
determine (including a term different from the term, rental concessions, and
alterations to, and improvement of, the Leased Premises); however, Lessor shall
not be obligated to relet the Leased Premises before leasing other portions of
the Building.  Lessor shall not be liable for, nor shall Lessee's obligations
hereunder be diminished because of, Lessor's failure to relet the Leased
Premises or to collect rent due for such reletting.  Lessee shall not be
entitled to the excess of any consideration obtained by reletting over the rent
due hereunder.  Re-entry by Lessor in the Leased Premises shall not affect
Lessee's obligations hereunder for the unexpired term; rather, Lessor may, from
time to time, bring action against Lessee to collect amounts due by Lessee,
without the necessity of Lessor's waiting until the expiration of the term.
Unless Lessor delivers written notice to Lessee expressly stating that it has
elected to terminate this Lease, all actions taken by Lessor to exclude or
dispossess Lessee of the Leased Premises shall be deemed to be taken under this
Section 11.2b. If Lessor elects to proceed under this Section 11.2b., it may at
any time elect to terminate this Lease under Section 11.2a.

         c.   In addition to its rights under 11.2(a) and (b) above, Lessor
may, without notice, alter locks or other security devices at the Leased
Premises to deprive Lessee of access thereto, and Lessor shall not be required
to provide a new key or right of access to Lessee so long as any Event of
Default exists.


11.3  Payment by Lessee.

         Upon any Event of Default, Lessee shall pay to Lessor all costs
incurred by Lessor (including court costs and reasonable attorneys' fees and
expenses) in (i) obtaining possession of the Leased Premises, (ii) removing and
storing Lessee's or any other occupant's property, (including the cost of
altering any locks or security devices), (iii) the reasonable cost of
repairing, restoring, altering, remodeling, or otherwise putting the Leased
Premises into condition acceptable to a new tenant, (iv) if Lessee is
dispossessed of the Leased Premises and this Lease is not terminated, reletting
all or any part of the Leased Premises (including brokerage commissions, cost
of tenant finish work, and other costs incidental to such reletting), (v)
performing Lessee's obligations which Lessee failed to perform, and (vi)
enforcing, or advising Lessor of, its rights, remedies, and recourse arising
out of the Event of Default.

11.4 Performance by Lessor.

         If Lessee defaults under this Lease, Lessor, without waiving or curing
the default, may, but shall not be obligated to, perform Lessee's obligations
for the account and at the expense of Lessee. Notwithstanding Section 11.1b, in
the case of an emergency, Lessor need not give any notice prior to performing
Lessee's obligations.  Lessee irrevocably appoints Lessor and Lessor's
successor and assigns, with full power of substitution, as  Lessee's
attorney-in-fact, coupled with an interest, to execute, acknowledge and deliver
any instruments in connection with Lessor's performance of Lessee's obligations
if Lessee is in default, and to take all other acts in connection therewith.

11.5 Post-Judgment Interest.

         The amount of any judgment obtained by Lessor against Lessee in any
legal proceeding arising out of Lessee's default under this Lease shall bear
interest until paid at the maximum rate allowed by law, or, if no maximum rate
prevails, at the rate of eighteen percent (18%) per annum. Notwithstanding
anything to the contrary contained in any laws, with respect to any damages
that are certain or ascertainable by calculation, interest shall accrue from
the day that the right to the damages vests in Lessor, and in the case of any
unliquidated claim, interest shall accrue from the day the claim arose.

                            ARTICLE 12. - RELOCATION

12.1  Deleted.

12.2  Deleted.





                                       14

<PAGE>   15


                           ARTICLE 13. - DEFINITIONS

13.1  Deleted.

13.2  Act of God or Force Majeure.

         An "act of God" or "force majeure" is defined for purposes of this
Lease as strikes, lockouts, sitdowns, material or labor restrictions by any
governmental authority, unusual transportation delays, riots, floods, washouts,
explosions, earthquakes, fire storms, weather (including wet grounds or
inclement weather which prevents construction), acts of the public enemy, wars,
insurrections, and/or any other cause not reasonably within the control of
Lessor or which by the exercise of due diligence Lessor is unable wholly or in
part, to prevent or overcome.


13.3  Net Rentable Area.

         "Net Rentable Area" or "NRA" as used in this Lease includes the area
contained within the Leased Premises together with a common area percentage
factor of the Leases Premises proportionate to the total building area as
determined by Lessor.  It is agreed that upon completion of the construction of
the Lessee Finish-Work as provided in Exhibit "D", if necessary an adjustment
shall be made to reflect the true net rentable area of the Leased Premises.
Such amendment shall be executed within thirty (30) days after occupancy by
Lessee and once amended there shall be no further adjustment.

                          ARTICLE 14. - MISCELLANEOUS

14.1   Waiver.

         Failure of Lessor to declare an event of default immediately upon its
occurrence, or delay in taking any action in connection with an event of
default, shall not constitute a waiver of the default, but Lessor shall have
the right to declare the default at any time and take such action as is lawful
or authorized under this Lease.  Pursuit of any one or more of the remedies set
forth in Article 11 above shall not preclude pursuit of any one or more of the
other remedies provided elsewhere in this Lease or provided by law, nor shall
pursuit of any remedy hereunder or at law constitute forfeiture or waiver of
any rent or damages accruing to Lessor by reason of the violation of any of the
terms, provisions or covenants of this Lease.  Failure by Lessor to enforce one
or more of the remedies provided hereunder or at law upon any event of default
shall not be deemed or construed to constitute a waiver of the default or of
any other violation or breach of any of the terms provisions and covenants
contained in this Lease.  Lessor may collect and receive rent due from Lessee
without waiving or affecting any rights or remedies that Lessor may have at law
or in equity or by virtue of this Lease at the time of such payment.
Institution of a forcible detainer action to re-enter the Leased Premises shall
not be construed to be an election by Lessor to terminate this Lease.

14.2  Act of God.

         Lessor shall not be required to perform any covenant or obligation in
this Lease, or be liable in damages to Lessee, so long as the performance or
non-performance of the covenant or obligation is delayed, caused or prevented
by an act of God, force majeure or by Lessee.

14.3  Attorney's Fees.

         If Lessee defaults in the performance of any of the terms, covenants,
agreements or conditions contained in this Lease and Lessor places in the hands
of any attorney the enforcement of all or any part of this Lease, the
collection of any rent or other sums due or to become due or recovery of the
possession of the Leased Premises, Lessee agrees to pay Lessor's costs of
collection, including reasonable attorney's fees, whether suit is actually
filed or not.





                                       15

<PAGE>   16
14.4  Successors.

         This Lease shall be binding upon and inure to the benefit of Lessor
and Lessee and their respective heirs, personal representatives, successors and
assigns.

14.5  Rent Tax.

         If applicable in the jurisdiction where the Leased Premises are
situated, Lessee shall pay and be liable for all rental, sales and use taxes or
other similar taxes, if any, levied or imposed by any city, state, county or
other governmental body having authority, such payments to be in addition to
all other payments required to be paid to Lessor by Lessee under the terms of
this Lease.  Any such payment shall be paid concurrently with the payment of
the rent, additional rent, operating expenses or other charge upon which the
tax is based as set forth above.

14.6  Interpretation.

         The captions appearing in this Lease are for convenience only and in
no way define, limit, construe or describe the scope or intent of any Section.
Grammatical changes required to make the provisions of this Lease apply (1) in
the plural sense where there is more than one tenant and (2) to limited
liability companies, corporations, associations, partnerships or individuals,
males or females, shall in all instances be assumed as though in each case
fully expressed.  The laws of the State of Texas shall govern the validity,
performance and enforcement of this Lease. This Lease shall not be construed
more or less favorably with respect to either party as a consequence of the
Lease or various provisions hereof having been drafted by one of the parties
hereto.

14.7  Notices.

         All rent and other payments required to be made by Lessee shall be
payable to Lessor, in care of Manager, at Manager's address set forth on page
1.  All payments required to be made by Lessor to Lessee shall be payable to
Lessee at Lessee's address set forth on page 1. Any notice or document (other
than rent) required or permitted to be delivered by the terms of this Lease
shall be deemed to be delivered (whether or not actually received) when
deposited in the United States Mail, postage prepaid, certified mail, return
receipt requested, addressed to the parties at the respective addresses set
forth on page 1 (or, in the case of Lessee, at the Leased Premises), or to such
other addresses as the parties may have designated by written notice to each
other, with copies of notices to Lessor being sent to Lessor's address as shown
on page 1.  Manager shall be a co-addressee with Lessor on all notices sent to
Lessor by Lessee hereunder, and any notice sent to Lessor and not to Manager,
also, in accordance with this section shall be deemed ineffective.

14.8  Submission of Lease.

         Submission of this Lease to Lessee for signature does not constitute a
reservation of space or an option to Lease.  This Lease is not effective until
execution by and delivery to both Lessor and Lessee.

14.9  Authority.

         Lessee represents and warrants to Lessor that:  Lessee is a duly
authorized and existing Texas  corporation, Lessee is qualified to do business
in the state in which the Leased Premises are located,   Lessee  has full right
and authority to enter into this Lease, each person signing on behalf of
Lessee is authorized to do so, and the execution and delivery of the Lease by
Lessee will not result in any breach of, or constitute a default under any
mortgage, deed of trust, lease, loan, credit agreement, partnership agreement,
or other contract or instrument to which Lessee is a party or by which Lessee
may be bound.

14.10 Deleted.

14.11 Deleted.





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14.12 Severability.

         If any provision of this Lease or the application thereof to any
person or circumstances shall be invalid or unenforceable to any extent, the
remainder of this Lease and the application of such provisions to other persons
or circumstances shall not be affected thereby and shall be enforced to the
greatest extent permitted by law.  Each covenant and agreement contained in
this Lease shall be construed to be a separate and independent covenant and
agreement, and the breach of any such covenant or agreement by Lessor shall not
discharge or relieve Lessee from Lessee's obligation to perform each and every
covenant and agreement of this Lease to be performed by Lessee.

14.13 Lessor's Liability.

         If Lessor shall be in default under this Lease and, if as a
consequence of such default, Lessee shall recover a money judgment against
Lessor, such judgment shall be satisfied only out of the right, title, and
interest of Lessor in the Property as the same may then be encumbered and
neither Lessor nor any person or entity comprising Lessor shall be liable for
any deficiency.  In no event shall Lessee have the right to levy execution
against any property of Lessor nor any person or entity comprising Lessor other
than its interest in the Property as herein expressly provided.

14.14  Deleted.

14.15 Time is of the Essence.

         The time of the performance of all of the covenants, conditions and
agreements of this Lease is of the essence of this Lease.

14.16 Subtenancies.

         At Lessor's option, the voluntary or other surrender of this Lease by
Lessee, or a mutual cancellation thereof, shall not work a merger of estates
and shall operate as an assignment of any or all permitted subleases or
subtenancies.

14.17 Name.

         Lessee shall not use the name of the Building or of the development in
which the Building is situated, if any, for any purpose other than as an
address of the business to be conducted by Lessee in the Premises.

14.18 Choice of Law.

         This Lease shall be governed by the laws of the State of Texas
applicable to transactions to be performed wholly therein.

14.19 Presumptions.

         This Lease shall be construed without regard to any presumption or
other rule requiring construction against the party drafting the document. It
shall be construed neither for nor against Lessor or Lessee, but shall be given
reasonable interpretation in accordance with the plain meaning of its terms and
the intent of the parties.

14.20 Exhibits.

         All exhibits and any riders annexed to this Lease are incorporated
herein by this reference.

14.21 Brokers.





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<PAGE>   18
         Lessee represents and warrants to Lessor that Lessee has had no
dealings with any broker, finder, or similar person who is or might be entitled
to a commission or other fee in connection with introducing Lessee to the
Building or in connection with this Lease. Lessor shall pay the commission due
Lessor's Broker pursuant to a separate agreement between Lessor and Lessor's
Broker.  Lessee shall indemnify Lessor for, and hold Lessor harmless from and
against, any and all claims of any person other than Lessor's Broker who claims
to have introduced Lessee to the Building or dealt with Lessee in connection
with this Lease and all liabilities arising out of or in connection with such
claims.

                        ARTICLE 15. - SPECIAL PROVISIONS

15.1    Right of First Refusal on Adjacent Space.

         During the term of this Lease, Lessee shall have the continuing right
of first refusal to acquire additional lease space adjacent to the Leased
Premises.  Lessor agrees to give notice as provided herein to Lessee of any
proposed new leases, as such leases may be presented, from time to time, on
space adjacent to the Leased Premises allowing Lessee the option to acquire
such space on similar terms and conditions as those offered by Lessor to any
third parties.  Notice of such proposed lease shall be given to Lessee by
Lessor along with the basic terms of the proposed lease.  Lessee shall have
fifteen (15) days in which to reply in writing to Lessor indicating its
decision with regard to exercising its option rights.

              ARTICLE 16. - AMENDMENT AND LIMITATION OF WARRANTIES

16.1  Entire Agreement.

         EXCEPT FOR THE LETTER AGREEMENT DATED OCTOBER 23, 1996, IT IS
EXPRESSLY AGREED BY LESSEE, AS A MATERIAL CONSIDERATION FOR THE EXECUTION OF
THIS LEASE, THAT THIS LEASE, WITH THE SPECIFIC REFERENCES TO EXTRINSIC
DOCUMENTS, IS THE ENTIRE AGREEMENT OF THE PARTIES: THAT THERE ARE, AND WERE, NO
VERBAL REPRESENTATIONS, WARRANTIES, UNDERSTANDINGS, STIPULATIONS, AGREEMENT OR
PROMISES PERTAINING TO THE SUBJECT MATTER OF THIS LEASE OR OF ANY EXPRESSLY
MENTIONED EXTRINSIC DOCUMENTS THAT ARE NOT INCORPORATED IN WRITING IN THIS
LEASE.

16.2  Amendment.

         THIS LEASE MAY NOT BE ALTERED, WAIVED, AMENDED OR EXTENDED EXCEPT BY
AN INSTRUMENT IN WRITING SIGNED BY LESSOR AND LESSEE.

16.3  Limitation of Warranties.

         LESSOR AND LESSEE EXPRESSLY AGREE THAT THERE ARE AND SHALL BE NO
IMPLIED WARRANTIES OF MERCHANTABILITY, HABITABILITY, FITNESS OF A PARTICULAR
PURPOSE OR OF ANY OTHER KIND ARISING OUT OF THIS LEASE, AND THERE ARE NO
WARRANTIES WHICH EXTEND BEYOND THOSE EXPRESSLY SET FORTH IN THIS LEASE.
WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, LESSEE EXPRESSLY ACKNOWLEDGES
THAT LESSOR HAS MADE NO WARRANTIES OR REPRESENTATIONS CONCERNING ANY HAZARDOUS
SUBSTANCES OR OTHER ENVIRONMENTAL MATTERS AFFECTING ANY PART OF THE PROPERTY,
AND LESSOR HEREBY EXPRESSLY DISCLAIMS AND LESSOR WAIVES ANY EXPRESS OR IMPLIED
WARRANTIES WITH RESPECT TO ANY SUCH MATTER.

16.4  Waiver and Releases.

         LESSEE SHALL NOT HAVE THE RIGHT TO WITHHOLD OR TO OFFSET RENT OR TO
TERMINATE THIS LEASE EXCEPT AS EXPRESSLY PROVIDED HEREIN.  LESSEE WAIVES AND
RELEASES ANY AND ALL STATUTORY LIENS AND OFFSET RIGHTS.





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<PAGE>   19
EXECUTED to be effective the date first above written.


LESSOR


FASKEN CENTER, LTD.
By:  550 Texas, Inc., General Partner




By:  /s/ WENDELL L. BROWN, JR.
   ----------------------------
Name:  Wendell L. Brown, Jr.
      -------------------------
Title:  Vice President
      -------------------------
                            

LESSEE



VISTA RESOURCES, INC.





By:  /s/ C. RANDALL HILL
   ----------------------------
Name:  C. Randall Hill
     --------------------------
Title:  Chief Executive Officer
      -------------------------




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