
Waclaw Sierpinski (18821969), a Polish mathematician working in number theory and set theory, described the selfrepeating, or fractal design shown on the Finnish stamp at left. Sierpinski triangles are created by connecting the the midpoints of the sides of a triangle to form four smaller, interior triangles, and then repeating this process for each of the outside three triangles, ad infinitum. A Hungarian stamp commemorating a mathematical congress shows a design of Sierpinski pyramids, with Michelangelo's hand of God from the Sistine Chapel ceiling thrown in for good measure.A full description of the Polish School of Mathematics appears here. Some of its illustrious members included in a set with Sierpinski are Stanislaw Zaremba (18631942), Stefan Banach (18921945), and Zygmunt Janiszewski (18881920). 