Place thirteen pentominos on in an 8x8 box.
The program finds all 129168 solutions in about 20 minutes (including writing all solutions to a file).
One such solution is:
12 12 12 10 10 10 10 3
12 12 11 4 4 10 3 3
6 11 11 11 4 3 3 9
6 6 6 11 4 4 9 9
6 2 2 2 2 2 9 8
5 5 5 7 7 0 9 8
5 1 1 7 0 0 0 8
5 1 1 7 7 0 8 8