Yin Yang

Yin Yang is a logic puzzle where players fill a grid with red and yellow cells. No 2-by-2 block can be all one color, and all the red cells must connect, just as all the yellow cells must connect. Students tap to switch a cell and then look at how that choice changes the rest of the board.

The rules force careful lookahead. Learners practice pattern recognition, spatial reasoning, and the same connectivity ideas used in path and region puzzles. Starting on a 3-by-3 grid and growing from there, the game asks them to persist, undo, and try another arrangement.

PlayMath.org and the Julia Robinson Mathematics Festival have partnered to bring some of the real-world activities from the math festivals to life online. JRMF is a nonprofit that hosts non-competitive math festivals, where K–12 students explore hands-on puzzles together.