Seller agrees on or before _________ days from the date of this contract to construct in the subdivision streets, curbs and gutters, and to install in the subdivision water lines, in accordance with requirements of law and of the City of _________ governing subdivisions. In the event seller does not complete the above-described construction within the _________-day period, purchaser at h— option may have return of the _________ dollars in escrow, and this contract shall then become void. However, in the event seller does not complete h— obligation within said _________-day period, purchaser shall have the option of allowing this contract to remain in full force for an additional _________-month period during which time seller shall have the right to make the improvements. In the event seller has not completed the improvements within the additional _________-month period, purchaser shall have the option to treat this contract as void, to have return of the _________ dollars in escrow, and to recover from seller liquidated damages in the sum of _________ dollars since purchaser will suffer substantial damages difficult to measure, or to have this contract of sale executed according to its terms except as to the making of the improvements by seller and except that the purchase price shall then be $_____.