In 2005 Macau issued a set of stamps featuring fractal patterns. These have the property of being self-similar – they reproduce themselves infinitely often when magnified or reduced. Among the topics depicted were constructions for the *Cantor set* (an infinite set of points that contains no interval) the *snowflake curve* of Helge von Koch (of infinite length, but enclosing a finite area),* Hilbert’s space-filling curve*, the *Sierpinski triangle* and a fractal tree pattern.

When a recurrence of the type *z _{n}*

*[Israel 1997; Macau 2005]*