Three Piece Block

Designed, made, and sold by Stewart Coffin in 1970's and early 1980's.
(mahogany, 3 pieces, 4 inches;
one of 6 puzzles purchased during a visit with the designer in the early 1980's)

Described in Stewart Coffin's book The Puzzling World of Polyhedral Dissections; here is some of what he says in the directions that came with the puzzle:
"The one symmetrical face of the assembled puzzle happens to resemble a certain corporate logo. The company wanted a simple puzzle incorporating this pattern for some sort of promotional scheme. So the arrangement of six of the blocks was already determined. All that was required to complete the design was the addition of four more blocks in a sort of triangular pyramid and a judicious choice of glue joints to make it into an interesting interlocking puzzle. So the company got what they wanted - except for one thing. It turned out to be anything but simple!"
When apart, it is hard to visualize what it is supposed to look like when assembled (although once assembled, you know you have it). Here are photos showing the piece orientations for assembly and the first of the two steps that puts together the two three block pieces: