Irregular polyhedra

[mklotz]

Assumptions: 7 blocks in set, 5 blocks selected and that subset used to build stack

The number of combinations of n things taken m at a time is given by n! / [(n-m)!*m!]

so number of unique subsets = 7! / [2!*5!] = 6*7 / 2 = 21

with each subset, we have 5 choices for the first block, 4 for the second,etc.... so 5! = 120 arrangements.

Therefore, given the initial assumptions, 21 * 120 = 2520 unique stacks