Passion For Puzzles

On a Japanese site called Aura Collection I found a puzzle called Plenus 21 and is designed by Peer Clahsen. Although the puzzle is sold out it's looks very nice and interesting. The puzzle is solved when it is subdivided into a number of unequal squares (net), or reversed, when several squares are completely put together as a square. Plenus 21 forms a "perfect" square block. Peer Clahsen discovered the base code of Plenus 21 (linking of a smallest possible square) in 1976. Each different square consisted of 21 squares is put into one square.