Designed by Jerry Loo, made by Eric Fuller, 2016.
(Maple, Mahogany, Walnut, Acrylic, 6" x 3.75" x 3/4";
removable acrylic cover has starting position etched on it)
Exchange pieces A and B and finish with the other pieces in their original positions.
Below are selected steps,
including every step in which piece X moves,
of a solution of
33 rectilinear steps
(53 straight-line steps, 74 unit steps).
Note that at step 22 pieces A and B are exchanged,
and the remaining steps put the other pieces back.