I already sought answers on three different forums without success. I hope I will be lucky this time.
I tried to find non-trivial solutions on a deficient 8×8 grid covered with trominoes and I regret to say that after extensive efforts I found only two non-trivial solutions:
The conditions of covering such a grid with trominoes are the following: In total we have 21 L-shaped trominoes with 3 different colors. There are equal numbers of trominoes of each color. Placing the trominoes on the grid, no 2 trominoes of the same color are allowed to touch each other anywhere, except only once, corner to corner (highlighted by red lines in the diagram).
Solutions from rotations and reflections are trivial. Does anyone know how to obtain more non-trivial solutions? Please include the full 8X8 grid in your answers.