回复：ZT：平面上7个点（3星）

来源: 于 2009-07-03 06:52:26 [旧帖] [给我悄悄话] 本文已被阅读：次

A. 3 points form a triangle with each edge of 1.
B. 4 points form a square with each edge of 1.
place A and B at a plane separated far enough that any point in one group to any point of another group is large than 1.