Contest 6

Make a stairway, with stairfoot and stairhead 1, and no landing, using six different pentominoes..
Double the size of the stairway by using two sets of pentominoes.
The pentominoes must touch along the full edge of the square and not just at the corners.
The area enclosed by the stairway must be one part.
When making the big stairway, no identical pentominoes may touch each other, not even with the corners.
Try to maximize the number of steps.
The stairway in our example has 11 steps.

Do you have our exel file? You can download it here.
Je kunt het hier downloaden

'FlatPoly 2', a programm by Aad van de Wetering, can be of great assistance when trying to find a solution. It can be downloaded at his site.