Hoffman's "Nut" burr puzzle

From Hoffmann's 1893 book _Puzzles Old and New_, via Martin Gardner's Scientific American column sometime in the late 70s/early 80s, via my childhood memory, via Blender. I made many of these in balsa wood as a kid. Not very hard by the now-well-known analysis.

Disassembly video is at: http://youtu.be/8Efjz7pOQqU