Four-Piece Serially Interlocking Cube (STC-93)

Designer: Stewart T. Coffin
Puzzle type/category: Cubic dissection, Interlocking
Difficulty level: ?
Material: Various wood species.

I discovered this puzzle in Brian Menold's book, WOODEN PUZZLES. I made several versions, as seen here.

Material: Purpleheart, Sapele, Canarywood