A shape that can be tiled with smaller congruent copies of itself is called a rep-tile . If the tiling uses copies, the shape is said to be of order . A shape that tiles itself using copies of different sizes is called an irregular rep-tile or ir-rep-tile. This Demonstration is limited to ir-rep-tiles of order two with compact disk-like shape and fractal boundary. Only a few such ir-rep-tiles are known. Hinsley  has listed seven such ir-rep-tiles of order two. Here, nine such ir-rep-tiles are shown.
All examples are related to roots of the polynomial with . Approximations of the fractal tilings are produced by an iterated function system (IFS) using the chaos game method. Example 2 is the well-known Hokkaido tiling, named by Shigeki Akiyama in reference to the Japanese island with the same name.