|I had always been interested in designing burr puzzles which are
difficult to take apart. The burr shapes I had used to this point all had the
same symmetry as the 6-piece burr or the 24-piece burr - mathematically
there are 24 symmetries to these shapes. However, keeping all these symmetries
and creating a new shape resulted in burrs with lots of pieces.
Starting with the Wausau'81 burr, I experimented with shapes which had
different 'patterns' of rods along the 3 axes.
Wausau'81 has 12 pieces and is non-trivial to take apart.