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                                                                   EXHIBIT 10.16


                              AMENDMENT NUMBER ONE


AMENDMENT NUMBER ONE TO THAT LEASE DATED NOVEMBER 23, 1998 BETWEEN SPIEKER
PROPERTIES, L.P., AS LANDLORD, AND POET SOFTWARE CORPORATION, AS TENANT (THE
"LEASE"), FOR PREMISED LOCATED AT 999 BAKER WAY, SAN MATEO, CALIFORNIA.

Effective approximately May 1, 2000, the Lease will be amended as follows to
provide for Tenant's expansion premises and extension of Lease term:

1.   PREMISES. The term "Premises" as used in the Lease is amended to mean
     approximately 12,118 square feet of rentable area located on the second
     floor of the building known as San Mateo Bay Center III. The Premises as
     expanded herein are approximately as shown outlined in red on the attached
     floor plan (Exhibit B - Suite 200). The square footage on the first floor
     shall be reduced to 0 square feet upon commencement of the 12,118 square
     feet on the second floor and pursuant to Paragraph 36.

2.   OCCUPANCY DENSITY. 3.2 people per 1000 square feet.

3.   RENT. Base Rent for the Premises as expanded herein shall be as follows:

     5/01/00 - 4/30/01   Forty thousand seven hundred sixteen dollars and
                         00/100ths dollars ($40,716.00) per month plus operating
                         expenses per Paragraph 7 of the Lease. Operating
                         expenses through December 2000 are estimated to be
                         $10,785.00 per month. Direct operating expenses are
                         estimated a year in advance and collected on a monthly
                         basis. Any adjustments necessary (up or down) will be
                         made at the end of the operating year.

     5/01/01 - 4/30/02   Forty one thousand nine hundred twenty eight dollars
                         and 00/100ths dollars ($41,928.00) per month plus
                         operating expenses per Paragraph 7 of the Lease.

     5/01/02 - 4/30/03   Forty three thousand one hundred forty dollars and
                         00/100ths dollars ($43,140.00) per month plus operating
                         expenses per Paragraph 7 of the Lease.

     5/01/03 - 4/30/04   Forty four thousand four hundred seventy three and
                         00/100ths dollars ($44,473.00) per month plus operating
                         expenses per Paragraph 7 of the Lease.

4.   SECURITY DEPOSIT. The Security Deposit under the Lease shall be increased
     by $29,973.00 for a total Security Deposit of $44,473.00, payable upon
     execution of this Amendment Number One. The sums shall be held and owned by
     Landlord in an interest bearing account and as further defined in Paragraph
     19 of the Lease. Landlord shall have the obligation to pay interest to
     Tenant on an annual basis upon the anniversary month of the Lease.

5.   TENANT'S PROPORTIONATE SHARE. 19.28%

6.   TENANT IMPROVEMENTS. Tenant agrees to accept the Premises as so expanded in
     "as is" condition except for the improvements as described on the attached
     Exhibit A.

7.   EARLY ACCESS. Tenant shall have access to the Premises (15) fifteen days
     prior to the Effective Date for the purposes of performing cabling, wiring
     or other communications related work. Tenant shall not reasonably interfere
     with, disturb or delay construction by Landlord.
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8.   RE-LEASING OF PREMISES. From and after the date of this Agreement,
     Landlord shall have full access to the existing premises on the ground
     floor at all times reasonable to Tenant and Landlord in order to show the
     premises to prospective tenants. Tenant agrees that Landlord may enter
     into a new lease for the existing premises with any third party prior to
     the Effective Date and that Tenant shall have no right to any amounts
     received by Landlord in connection therewith.

All other terms and conditions of the Lease shall remain in full force and
effect and shall apply to the Premises as well as to the original premises.

Dated: January 19, 2000

IN WITNESS WHEREOF, the premises hereto have executed this Amendment Number One
as of the day and year first above written.

LANDLORD:

SPIEKER PROPERTY, L.P.,
a California limited partnership

By: Spieker Properties, Inc.,
    a Maryland corporation,
    its general partner

    By:  /s/ NANCY GILLE
         --------------------------
         Nancy Gille

    Its: Vice President
         -------------------------


TENANT:

POET SOFTWARE CORPORATION.
a Massachusetts corporation


By: /s/  JERRY WONG
    --------------------------
    Jerry Wong

Its: Vice President of Finance
     -------------------------
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                                   EXHIBIT A

                          LEASE IMPROVEMENT AGREEMENT


1.   In consideration of the mutual covenants contained in the Lease of which
     this EXHIBIT A is a part, Landlord agrees to perform the following initial
     tenant improvement work in the Premises ("TENANT IMPROVEMENTS"):

               a)   steam clean carpets,

               b)   paint interior walls,

               c)   install a sink, lower cabinets and possibly a dishwasher in
                    a location mutually agreeable to Landlord and Tenant,

               d)   create an opening between two separate spaces in a location
                    mutually agreeable to Landlord and Tenant,

               e)   demolish necessary walls to create a conference room with
                    possibly some floor to ceiling glass in a location that
                    shall be determined by Tenant.

The cost to the Landlord for tenant improvement work described in items c, d and
e above shall not exceed $12,118.00.

     2.   All the Tenant Improvements described above shall be performed by
Landlord at its cost and expense using Building Standard materials and in the
Building Standard manner. As used herein, "Building Standard" shall mean the
standards for a particular item selected from time to time by Landlord for the
Building or such other standards as may be mutually agreed upon between Landlord
and Tenant in writing.

     3.   Without limiting the "as-is" provisions of the Lease, Tenant accepts
the Premises in its "as-is" condition and acknowledges that Landlord has no
obligation to make any changes or improvements to the Premises or to pay any
costs expended or to be expended in connection with any such changes or
improvements, other than the Tenant Improvements specified in Paragraph 1 of
this EXHIBIT A.

     4.   Tenant shall not perform any work in the Premises (including, without
limitation, cabling, wiring, fixturization, painting, carpeting, replacements or
repairs) except in accordance with Paragraphs 12 and 27 of the Lease. Landlord
shall not require prior written consent for cabling, wiring and other
communications related work resulting from the relocation to the second floor,
however, said work shall otherwise be performed in accordance with Paragraphs 12
and 27.

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                                   EXHIBIT B



                                  [FLOOR PLAN]