Designed and made by Diniar Namdarian, 2016; sleeve made by J. A. Storer.
(laser cut plastic, oval 4+1/8" high by 7.5" long x 3/8" thick)

Two layers, where the butterflies are attached to single squares going down the diagonal below; the upper blue is attached to position (1,1), the lower blue is attached to position (2,2), the upper green is attached to position (3,3), and the lower green is attached to position (4,4), and the problem is to exchange the butterflies. A 52 rectilinear moves (68 straight-line moves) solution is possible; here is every 4th step of a 52 moves solution shown in the puzzle directions.