4 ominoes placed.
 1 2 2 2 2 2
 1 0 0 0 0 3
 1 0 0 0 0 3
 1 0 0 0 0 3
 1 0 0 0 0 3
 4 4 4 4 4 3

4 ominoes placed.
 1 1 1 1 1 2
 3 0 0 0 0 2
 3 0 0 0 0 2
 3 0 0 0 0 2
 3 0 0 0 0 2
 3 4 4 4 4 4

Done.  2 solutions found.