Sierpinsky Triangle or the Sierpinsky Gasket is a fractal with an overall shape of an equilateral triangle which is recursively subdivided into other smaller equilateral triangles. Its default implementation occurs in 2D  but it can be implemented in 3D by using pyramids. There are several slight alterations that can be made to it to generate other famous curves, such as the Arrowhead Curve or even certain Cellular Automaton displays.