Double Square Puzzle - make a 4 pc then a 5 pc square
Mechanical puzzle - Wikipedia
Double Square (a.k.a Square Me, Five Block Puzzle, Madagascar Madness)" - Copyright J. A. Storer
It Doesn't FIT 1510 Solving the EVIL Double Square Puzzle!! - Level 10 33M Views 4 Days Ago That Piece Does Fit You Flip It Over | Facepalm Meme on ME.ME
Double Square (a.k.a Square Me, Five Block Puzzle, Madagascar Madness)" - Copyright J. A. Storer