ASU 572 Commonwealth of Independent States 1991 bw cells in 2mxn board
Source:
August 15, 2019
Coloringtablevectorcombinatorics
Problem Statement
Half the cells of a board are colored black and the other half are colored white. The cells at the opposite ends of the main diagonal are different colors. The center of each black cell is connected to the center of every other black cell by a straight line segment, and similarly for the white cells. Show that we can place an arrow on each segment so that it becomes a vector and the vectors sum to zero.