Puzzling Times: Double Squared, a.k.a. Black or White
Two Sliding Squares" - Copyright J. A. Storer
5 Piece Square Puzzle Challenge | Math = Love
Double Squared - Art of Play
Double Squared Solution : r/puzzle
Amazon.com: Logica Puzzles Art. Double Tangram - Brain Teaser in Fine Wood for 1/2 Players - 65 Puzzles in 1 - Educational Puzzle - Mind Puzzle : Toys & Games
Five Piece Square Puzzle with hints and solution
Double Square (a.k.a Square Me, Five Block Puzzle, Madagascar Madness)" - Copyright J. A. Storer