A agrees to construct a stairway on the south side of [his or her] lot, on the west side of the public square in the city of _________ and county of _________[name of state], at least _________ inches in the clear, with the hall on the second floor running to the rear end of the building, with a door in the rear end of the hall.

B, for the use of the hall and stairway jointly with A, agrees to build a middle wall of good stone foundation and _________ inch brick wall two stories high for 80 feet and 20 feet one story high; this wall is to be built half on each party's ground, and to be owned jointly by the parties, and B agrees to pay half of the cost of a tin roof over the hall, and to put good iron doors on each opening that [he or she] may make in the partition walls. At the completion of the stairway and hall, each party shall pay half the expenses of keeping the stairway and hall in repair.