Dog And Cat

Designed by Minoru Abe, produced in Japan circa 1990.
(cardboard box, wood tray, 8 wood pieces, and wood keeper, 5 by 5.25 by 1 inch)

There are four 1 unit square pieces, three 2/3 by 1 unit pieces, a large U piece that is 2+4/9 units wide, and a keeper piece that is 1 unit high by 2+4/9 units wide. The U piece has a lower area that can hold a 2/3 by 1 unit piece and a 2 unit distance between the upper prongs. The puzzle is to remove the keeper, slide the pieces to exchange the dog and cat, and return the keeper:

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Baxter's Page shows this puzzle in his Minoru Abe Gallery and indicates a solution of 67 rectilinear moves.

Further Reading
Baxter's Abe Gallery, from: http://www.johnrausch.com/SlidingBlockPuzzles/gallery.htm