Maya numerals
The ancient mayan civilization used a vigesimal (base-20) numbering system.
The numerals are made up of three symbols; zero (egg shape), one (a dot) and five (a bar).
For example, 19 is
.... ____ ____ ____
Digits are stacked with the higher significant digits at the top, so
: =
would be read as 31.
See also: Arabic numerals, Chinese numerals, Roman numerals, Hebrew numerals