Checkers Font

by Jeffrey Bosboom, Spencer Congero, Erik Demaine, Martin Demaine, and Jayson Lynch, 2018


In this typeface, each letter and digit is represented by an 8 × 8 cooperative always-jumping checkers puzzle, where the red and black players cooperate to eliminate all pieces of one color by a sequence of moves, where every move jumps at least one piece (and jumps as many pieces as possible, because jumps are forced in checkers). Black always moves first, but does not always win. The pieces are all kings. Although the solutions are not unique, the movement of the pieces in any puzzle solution traces the letter or digit.

Our paper “Losing at Checkers is Hard” studies this type of checkers puzzle, and proves that it is NP-complete to solve in general. The small puzzles in this typeface are nonetheless easy to solve (being designed to be simple), and indeed your browser can solve them by exhaustive search in just a few milliseconds.

You can select three fonts in the typeface. The puzzle font just shows the puzzle, leaving the reader to find the solution and decode the letter. The solution font shows the puzzle and the move traces that will solve the puzzle, thereby also revealing the letter. The animated font shows the sequence of jumps that solve the puzzle, essentially starting from the puzzle font and ending at the solution font (but with only a single color of pieces at the end), gradually revealing the letter.

Check out other mathematical and puzzle fonts. • Feedback or not working? Email Erik.