16 checkers are placed on an 8 by 8 checkerboard, no two checkers on the same square. Show that some four of the 16 checkers are on the vertices of a parallelogram with positive area.

c _ c _ c _ c _
_ c _ c _ c _ c
c _ C _ _ _ C _
_ c _ c _ c _ _
C _ _ _ C _ _ _
_ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _

 

But I dont think thats what you ment. ^_^

Posted by Liz on 2005-07-19 03:48:15