Designed by William Hu, made by Eric Fuller, 2014.
(4 pieces, White Oak, Chakte Viga, 2" x 2" x 3")

This is what the puzzler maker says about the puzzle:
"This seemingly simple puzzle uses a very interesting and difficult type of rotation. Ultra tricky and not like anything I've tried before. Level nine and out, this one will have you pulling your hair out! Construction was tricky...the solid side spine and endgrain key pieces were fun to make, but very labor intensive. Fit is excellent; may be difficult to solve in highly humid environments due to the very close tolerances involved."
At first it looks like there is no way for it to come apart. If we number the pieces 1, 2, 3, 4 going from left to right, the trick to dissassembly is to tilt piece three and rotate piece two 90 degrees (clockwise as you look through the puzzle from left to right). The puzzle generally has a nice loose fit, but it is a tight fit at the point of the rotation.