a.k.a. The Third Degree
Designed by Bill Cutler, made by W. Hoppe, 1995.
(wood, 3.75 inches by 1.75 inches high)

Three pieces that are cut at odd angles (so that they not quite the same) must be placed into the box. Like the larger Block Head puzzle, putting them in one at a time will not work; to solve, first arrange them on the table so that the top surface is level and a hexagon, and then push them together at the bottoms and drop them into the box. Here is what the pieces look like in their solved positions, outside the box: