A ledge which is in front of a window, one may put onto it and take from it on the Sabbath. A person may stand in a private domain and move objects in a public domain, [or] in a public domain and move objects in a private domain; provided he does not take [them] beyond four cubits.

A person may not stand in a private domain and urinate into a public domain, [or] in a public domain and urinate into a private domain. Similarly, he may not expectorate. R’ Yehudah says: Even when one’s saliva has become detached in his mouth, he may not walk four cubits until he expectorates.