On Tue, 19 Nov 2002 asimovd@aol.com wrote:
Clearly any portion of a checkered board that can be covered by dominoes must have an equal number of squares of each color, but does the converse hold? d No! --- bc| | --------------- a| | | | |a --------------- | |cb --- R. d (Does identifiying opposite edges of the board to make a torus affect the answer?)
You said `any portion of'. If the portion is rectangular, then th answer is trivial, torus or otherwise. In the above board, if you identify a b c d ... you can tile the result. Is it a torus?? R.
AND: Would someone please recall for me a problem that was posted here several months ago, but never answered, regarding properties of some kind of balanced two-color designs on a 4x4 square.
Was this (something to do with) Barry Cipra's Sol LeWitt puzzle? P127 in The Inquisitive Problem Solver. R.
--Dan