With any polysquare or polyiamond you can ask whether such a shape tiles a square or triangle in an irregular way (using copies of various sizes). For this Demonstration the most interesting cases of irregular tilings have been selected.
Since the author's book was published on irreptiles, the problem area of irregular tilings has seen a steadily growing interest amongst puzzlists.
Many very simple cases of irregular tilings and a few very complicated cases are omitted in this Demonstration. Also excluded are all self-tilings of irreptiles; they are covered by the separate Demonstration "Irreptiles", created by the same author.
Contributions by other authors:
Rodolpho Kurchan: diagrams 10 and 30 Michael Reid: diagram 23 Tetsu Kawahara: diagram 29