A tiny Haskell program to solve a wooden block puzzle I once came across.

The puzzle consists of 10 wooden blocks, each one with 5 elements on one special surface.

The elements are either a hole, a pin or a blank.

The idea is to arrange the blocks with their special surfaces facing each other and the top layer at 90 degrees to the bottom layer, such that we always have:

Blank <-> Blank
Hole  <-> Pin
Pin   <-> Hole

The specification of the blocks is included in the source.