2007 BAMO p2 points in plane bw, if 3 of # have tha same color, so the 4th
Source:
August 27, 2019
combinatorial geometrycombinatoricsparallelogramColoring
Problem Statement
The points of the plane are colored in black and white so that whenever three vertices of a parallelogram are the same color, the fourth vertex is that color, too. Prove that all the points of the plane are the same color.