Exhibit 10.20

**AMENDMENT OF LEASE**

       **THIS AMENDMENT OFLEASE (this "Amendment") dated as of the 26th day of April, 2000, betweenVEF III FUNDING, LLC, a Delaware limited liability company, having an office c/oLendLease Real Estate Investments, Inc., 101 Arch Street, Boston, MA 02110("Landlord"), and INTERLEAF, INC., a Massachusetts corporation, having anaddress at 62 Fourth Avenue, Waltham, MA ("Tenant").**

**BACKGROUND**

       **Landlord and Tenant are Landlordand Tenant, respectively, under a Lease dated March 21, 2000 (the "Lease"),covering certain space on the first, second, third and fourth floors of thebuilding (the "Building") located at 400 Fifth Avenue, Waltham, MA (the"Original Premises"). The parties desire to add additional space on thesecond floor of the Building to the Original Premises under the Lease and toamend the Lease in certain other respects, all as hereinafter set forth.Capitalized terms not defined herein shall have the same meaning ascribed tothem in the Lease.**

**W I T N E S S E T H:**

       **NOW, THEREFORE, for good andvaluable consideration, the receipt and sufficiency of which are herebyacknowledged, the parties hereby agree as follows:**

        **1.    Section2.2 of the Lease is hereby amended by deleting the provisions thereof and bysubstituting therefor the following:**

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     **"Section 2.2.  Term.   TO HAVE AND TO HOLD for a term (hereinafter such term plus any extensions  hereof shall be referred to herein as the "Term" or "term") beginning  on the respective Term Commencement Dates described in Section 1.1 of this  Lease for the various components of the Premises and continuing until  September 30, 2006 (the "original term")."**

        2.   **Effective  on the "Additional Second Floor Premises Commencement Date" (defined  herein), there shall be added to the Premises under the Lease the portion of  the second floor of the Building shown as the "Additional Second Floor  Premises" on the plan attached hereto as Exhibit A-1 (the  "Additional Second Floor Premises"). The Additional Second Floor Premises  consists of approximately 7,073 rentable square feet of space. All of the  terms and provisions of the Lease (as amended hereby) shall be applicable to  the Additional Second Floor Premises except:**

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|  **(i)** |  | **the original term for the Additional Second Floor      Premises shall be the period commencing on the Additional Second Floor      Premises Commencement Date and ending on September 30, 2006; and****(ii)****the Annual Rent for the Additional Second Floor Premises      shall be as is set forth in Section 6 hereof.**
**        The "Additional SecondFloor Premises Commencement Date" shall be the earlier of (i) the date thatTenant occupies the same for purposes of commencing its business operations, or(ii) the date that is forty-five (45) days after the date that Landlordsubstantially completes "Landlord's Work for the Additional Second FloorPremises" (as such term is defined herein), as certified in writing byLandlord's contractor.**

**       3.   ****TheAdditional Second Floor Premises shall be leased to Tenant "as is", in itsthen present state of construction, finish and decoration, without anyobligation for preparation or construction therein by Landlord for Tenant'soccupancy or otherwise, except that Landlord shall complete the Buildingstandard fireproofing program for the Additional Second Floor Premises("Landlord's Work for the Additional Second Floor Premises"). Landlordagrees to use reasonable efforts to substantially complete construction ofLandlord's Work for the Additional Second Floor Premises within forty-five(45) days after the existing tenant (i.e., Dome imaging systems, inc.) vacatesthe same in its entirety (which vacation date is currently scheduled for August15, 2000). Landlord shall have no obligation to commence Landlord's Work forthe Additional Second Floor Premises until the current tenant has vacated theAdditional Second Floor Premises.**

        **All alterations, improvementsand additions by Tenant with respect to the****Additional Second FloorPremises shall be subject to all applicable provisions of the Lease (as amendedhereby).**

**        4.    Effectiveas of the Additional Second Floor Premises Commencement Date, Section 1.1 of theLease is hereby amended as follows:**
**(i)****By deleting the number "$66,575 per annum" from the      term "Tenant's Estimated Electrical Charge" and by substituting      therefor the number "$73,648 per annum";****(ii)****By deleting the percentage "58.13%" from the term      "Tenant's Proportionate Fraction" and by substituting therefor the      percentage "64.30%".**
**        5.   Landlord shall provide Tenant with a tenant improvement allowance in an amountnot exceeding $84,876 in the aggregate (the "Additional Second Floor PremisesAllowance") to reimburse Tenant for the costs incurred by Tenant in performinginitial leasehold improvements to the Additional Second Floor Premises and forthe other items described below in this Section 5, including but not limited toarchitectural and engineering**
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**consulting costs, moving costs, telecommunications equipment andinstallations and the purchase of office furniture, but subject, however, to thelimitations described in the next paragraph.**

   **     The Additional Second FloorPremises Allowance shall be paid to Tenant (in increments of not less $25,000),upon the submission to Landlord of a written requisition with copies of invoicessupporting the costs sought to be reimbursed and, if applicable, (a) lienwaivers from Tenant's contractors and (b) a certificate from Tenant's architectcertifying to the completion of the percentage of work sought to be reimbursed. Landlord shall pay each such approved requisition within twenty (20) days of itsreceipt.  Notwithstanding the foregoing, Landlord shall only be obligatedto pay such requisitions submitted by Tenant up to the aggregate amount of theAdditional Second Floor Premises Allowance and only to the extent that theamount described in such requisitions shall be included in the budget forTenant's work for the Additional Second Floor Premises that has been approved inwriting by Landlord prior to September 15, 2000.  At least 50% of theAdditional Second Floor Premises Allowance shall be expended for permanentleasehold improvements to the Additional Second Floor Premises,telecommunications wiring, equipment and installations, and architectural andengineering costs, and no more than 50% of the Additional Second Floor PremisesAllowance shall be expended for moving costs, the purchase of office furnitureand other consultant's costs.**

        **In no event, however, shallLandlord be obligated (i) to make any payments to Tenant on account of theAdditional Second Floor Premises Allowance prior to the Term Commencement Datefor the Additional Second Floor Premises or (ii) to make any payments to Tenanton account of the Additional Second Floor Premises Allowance for requisitionsreceived from Tenant after January 1, 2001, except if Tenant's failure to submita requisition prior to January 1, 2001 shall be due to Landlord's inability todeliver the Additional Second Floor Premises by November 1, 2001.**

**       6.    Commencing onAdditional Second Floor Premises Commencement Date, in addition to the AnnualRent that Tenant is obligated to pay to Landlord for the Original Premises,Tenant agrees to pay to Landlord Annual Rent for the Additional Second FloorPremises as follows:**
 **(a)****For the period commencing on the Additional Second Floor      Premises Commencement Date and ending on June 30, 2003: $190,971 per annum      ($15,914.25 per month); and** **(b)****For the period commencing on July 1, 2003 and ending on      September 30, 2006: $205,117 per annum ($17,093.08 per month).**
**        7.   Simultaneously with the execution and delivery of this Amendment by Tenant,Tenant shall deposit an additional $15,914.25 with Landlord to be held byLandlord, together with the $299,587.50 that Landlord is currently holding, asthe Security Deposit**
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**under the Lease so that, upon such delivery of such $15,914.25 amount toLandlord, the Security Deposit under the Lease shall be $315,501.75.**
        **8.    Except asonly expressly amended hereby, the Lease shall continue in full force and effectas heretofore.**
        **WITNESS the execution hereofunder seal as of the day and year first above written.**
**LANDLORD:** **VEF III FUNDING, LLC, a Delaware****limited liability company** **By:****Value Enhancement Fund III, LLC,** **a Georgia limited liability company,** **its manager** **By:****Lend Lease Real Estate****Investments, Inc., its manager** **By:****Name:** **Title:** **TENANT:** **INTERLEAF, INC.** **By:****Name:****Title:**
**EXHIBIT A-1[Attach Space Plan for Additional Second Floor Premises]**
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