Winkler's Level 3 Burr

Winkler's Level 3 Burr Design : David V. Winkler.

A#255 B#255 C#255
D#255 E#255 F#959
Pieces 6 A-E are congruent.
Length 6
Holes 9
Solutions 1 / 1
Moves 3

My question: Why doesn't he use #927 instead of #959?
Winkler answered: This was a burr to demonstrate a bug in the IBM web burr solver. The symmetric piece is more satisfying, but this one was the one that exposed the bug.

Apr 30, 2001 by k16@chiba.email.ne.jp