On November 17, 1790, German mathematician and astronomer August Ferdinand Möbius was born. He is best known for his discovery of the Möbius strip, a non-orientable two-dimensional surface with only one side when embedded in three-dimensional Euclidean space
On April 30, 1777, German mathematician and physical scientist Carl Friedrich Gauß was born. He who contributed significantly to many fields, including number theory, algebra, statistics, analysis, differential geometry, geodesy, geophysics, electrostatics, astronomy and optics. He is often referred to as Princeps mathematicorum (Latin, "the Prince of Mathematicians") as well as "greatest mathematician since antiquity".
On November 20, 1924, French American mathematician Benoite B. Mandelbrot was born. Mandelbrot worked on a wide range of mathematical problems, including mathematical physics and quantitative finance, but is best known as the popularizer of fractal geometry. He was the one who coined the term 'fractal' and described the Mandelbrot set named after him.
M. Mariotti. Proceedings of the 22nd Conference of the International Group for the Psychology of Mathematics Education, 1, page 180--195. Stellenbosch, South Africa, PME, University of Stellenbosch, (July 1998)