Coffin's 271A

Designed and made by Stewart Coffin, 2014.
(maple pieces and sides on plywood base, signed on the bottom;
2.25" high, top edges of walls are 2", balls are 3/4" diameter;
one of 4 puzzles purchased during a visit with the designer in 2014)

Unpacking requires moving the top two pieces out of the way and removing the bottom one first: