With Square Limits, M.C. Escher created a method to fill a square with an infinite number of triangles, whose size decreases with a smaller distance to the border. Additionally, the border line of the triangle can be altered to get more interesting shapes. However, with different textures of the triangles it is possible to create entirely different pictures.
If a triangle consists of one quadrant and one semicircle, we can get an infinite number of connected rings:
With a different texture, which basically consists of one point at one corner, we get shapes which resemble flying birds: