2 ms·
A slightly more involved version of this puzzle asks about covering all but one square of the chess board with 21 trominoes (each of size 3x1 or 1x3), since 64
by tromp 5y ago
A slightly more involved version of this puzzle asks about covering all but one square of the chess board with 21 trominoes (each of size 3x1 or 1x3), since 64 = 21*3 + 1.
What square remains uncovered (unique up to symmetry) ?