Shape

360 III Using It to Design
with the same repetition of numbers—5 ...5 or 3...3—at the end of both series.
Evidently, the order in which rectangles are added continues to be irrelevant, and
there’s no reason to keep a running count.
Given a grid of walls and with its description ðm; nÞ in hand, I know there are N
rooms, that is to say, N is given in the formula
N ¼ mn
This changes according to the description rule
N fi N
k
as I use rules to combine rectangles. In particular, for rules like these
that put rectangles together vertically, k ¼ 1 and k ¼ 2. Then, for rules like these
where spaces change horizontally, k ¼ 2. And for the cross that combines three
rectangles—two small ones and a big one—