Designed by Minoru Abe, this one made by J. A. Storer, 2010.
(Walnut tray, Cherry L's, Bloodwood square, 4.4" x 6.5" x 3/4")

Move the square from outside to insdie the L's. Here is the start and every other position of a 28 rectilinear moves (33 straight-line moves) solution: