Question 121
Each unit square of a $4 \times 4$ square grid is colored either red, green, or blue. Over all possible colorings of the grid, what is the maximum possible number of L-trominos that contain exactly one square of each color? (L-trominos are made up of three unit squares sharing a corner, as shown below.)
$$
\square \square \square \square \square \square \square
$$
$$
\square \square \square \square \square \square \square
$$