5. In the previous halacha we learnt that if a breach in a courtyard wall
is not wider than ten "amos" (1), it is viewed, halachically, as an
entrance, and no repairs are required [in order to retain the courtyard's
status as a private domain within which one may carry objects on Shabbos];
this rule, [however], only applies when there is only one breach [in the
wall]. If, however, there is more than one breach, [carrying is permitted
only] when the total width of the sections of the wall that are still
standing is at least equal in size to the total width of the gaps in the
wall. If, however, the total width of the gaps exceeds the total width of
the sections of wall that remain intact, every gap that is larger than
three "tefachim" (2) must be repaired (3).
(1) Opinions among the authorities as to the exact length of an "Amoh"
("cubit") range between 48 and 60cm (20 to 24 inches).
(2) Opinions among the authorities as to the exact length of a 'tefach'
('handbreadth') range between 8 and 10cm ( 3 to 4 inches)
(3) A gap which is less than three tefachim wide is, halachically, not
defined as a gap, but rather, is viewed as a continuation of the wall. This
is based on the principle called "Lovud" (See Shulchan Aruch 362:8).