If a wall between two courtyards is ten [fists] high and four wide, they may make two eruvin, but may not make one eruv. If there was fruit on top of it, these ascend from here and eat, and those ascend from there and eat, provided they do not bring down. If the wall was breached — up to ten cubits, they may make two eruvin, or, if they wish, one eruv, because it is like an entrance; greater than that, they may make one eruv, but may not make two eruvin.