Designed, made, and sold by Stewart Coffin in 1970's and early 1980's.
(Rosewood and Tulipwood, 6 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:
"This puzzle has the most unusual capability of being assembled into three different symmetrical solid shapes,
even though its six pieces are all identical in shape."
Four assembled shapes are shown in Stewart Coffin's book
Geometric Puzzle Design;
where he discusses the 4-piece
version of this puzzle.
One shape is the "star" shown above (6 points running vertically);
below are two ways to pull it apart into two sets of three pieces.
Another is the "hex ring" (a vertical hexagonal cylinder with a ring around the middle) that is show below,
and to its right a way to pull it apart. Note that rubber bands have been used in these figures
to hold pieces in place while photographed.