Design, copyright, and 3D print by J. A. Storer, 2022.
(plastic, 4 x 4 x 3/8 inches, with cardboard sleeve)

Inspired by the classic Work or Golf puzzle (which is based on a 5 x 4 grid), this puzzle is based on an "abridged" 4x4 grid where a "bridge" connects the O's (and forces them to move only left and right in lock-step). It can be done in 52 rectilinear moves.

Other words can be used to make effectively the same puzzle, so long as the second tiles on the top and bottom are the same. Using different colors, top and bottom words can have a letter in common (e.g. Cake and Bake). More than one letter on a tile is possible (e.g. M - A - R - S in G - A - LA - XY has a double character in the bottom two rightmost positions and WI - NI - N - G and DI - NI - N - G has a double character in the first two positions of both the top and bottom). Graphics could also be used instead of letters, such as a heart for L in ILNY (I Love New York).