Everyone is familiar with the usual rectangular stamps issued by all countries, but several countries have produced more unusual designs. Such stamps are issued for decorative reasons or are designed to represent a particular object, such as a rugby ball, a map of the country or a lunar module. There are even stamps from Tonga in the shape of a banana and a coconut.
Many countries have issued triangular stamps. These are usually equilateral or isosceles right-angled (either way up). Examples of scalene triangles, with all the angles and sides different, are rare; an early example is the scalene triangle of Colombia.
[Austria 1916; Colombia 1869; Ghana 1965; Malaysia 1966; Pakistan 1962]