The M-by-N puzzle
home instructions

To play this tromino puzzle, click and hold down the mouse key, dragging the yellow square to any desired square cell in the array shown, then release. Then fill in the remaining squares by the same mouse action, dragging the L-shaped tiles, called trominos, so eventually every empty square is covered exactly once by such a tile. Clicking on the Reset button erases the trominos and randomly places the yellow square in the array. Clicking on the Solve button will either complete the puzzle, if that is possible, or result in no progress if you have placed trominos so that no solution is ultimately possible. (Colors may change, but no solution will result.) Once a solution is achieved, clicking on the Recolor button changes the colors of the trominos into just four colors, in such a way that no two trominos sharing an edge have the same color.

Clicking on either of the two down arrow buttons at the top, left allows you to specify a new rectangular or square shape for the puzzle, having anywhere from 2 through 32 squares on a side. If you make an m×n rectangle and the product mxn is divisible by 3, no yellow square appears and you should try to fill the spaces with trominos only. If mn leaves remainder 1 upon division by 3, one yellow square appears and you can try to solve the puzzle just as in the original 8×8 case. If mn leaves remainder 2 upon division by 3, two yellow squares appear (these can be relocated if desired) and the goal again is to solve the puzzle by filling the remaining spaces with trominos.


This version of the puzzle was programmed
by Chris Eliot, Visiting Professor
Computer Science, Amherst College, Spring 2004