Richard McP. Cabeen, in his book, Standard Handbook of Stamp Collecting, provides some lists of philatelic firsts which he suggests might make a nice collection of the historical and educational aspects of stamps.  His third list dealt with stamp shapes.

SHAPES

Normal shape, vertical rectangle	Great Britain	1840
Horizontal rectangle	Brazil	1850
Rectangle, decorated	Brazil	1844
Rectangle, sides curved	Roman States	1852
Square, normal	Bavaria	1849
Square, on corner	Nova Scotia New Brunswick	1851
Triangle, right-angle isosceles, on hypotenuse	Cape of Good Hope	1853
Triangle, right-angle isosceles, on point	Latvia	1921
Triangle, right-angle, on hypotenuse	Columbia	1869
Triangle, equilateral, on side	Columbia	1865
Triangle, equilateral, on point	Austria	1916
Diamond, long axis horizontal	Somali Coast	1894
Diamond, long axis vertical	Lithuania	1923
Octagon, elongated vertically	Great Britain	1847
Octagon, elongated horizontally	Roman States	1852
Octagon, true	Portugal Tasmania	1853
Octagon, true, perforated as octagon	Thessaly	1898
Circle	Roman States	1852
Ellipse, vertical	New South Wales	1856
Map of the country, die cut	Sierra Leone	1964
Heart shape, die cut	Tonga	1961
Ellipse, vertical	New South Wales	1856
Shield	Argentina	1867
Star, six points	Columbia	1865

Posted September 24, 2000

Editor's Note:  There have been more shapes added in recent years.