Honorable Mention, 2014

Mathematicians have long wondered if you could fill in the squares of an 18 by 18 grid with four colors in such a way that it would be impossible to pick out a rectangular group of squares with the same color in all four of its corners. This grid demonstrates one of the solutions to this problem.

Credit:
Marijn Heule, Ph.D.
Center for Information Security, Department of Computer Science