Hamming’s Smart Error-correcting Codes

In the late 1940s, Richard Hamming, working at Bell Labs, was exasperated with the high level of errors occurring in the electro-mechanical computing equipment he was using. Punched card machines were constantly misreading, forcing him to restart his programs. He decided to do something about it. This was when error-correcting codes were invented. A simple … Continue reading Hamming’s Smart Error-correcting Codes →

The Ubiquitous Cycloid

Puzzle: However fast a train is travelling, part of it is moving backwards. Which part? For the answer, see the end of this post. Imagine a small light fixed to the rim of a bicycle wheel. As the bike moves, the light rises and falls in a series of arches. A long-exposure nocturnal photograph would … Continue reading The Ubiquitous Cycloid →

Holbein’s Anamorphic Skull

Hans Holbein the Younger, court painter during the reign of Henry VIII, produced some spectacular works. Amongst the most celebrated is a double portrait of Jean de Dinteville, French Ambassador to Henry's court, and Georges de Selve, Bishop of Lavaur. Painted by Holbein in 1533, the picture, known as The Ambassadors, hangs in the National … Continue reading Holbein’s Anamorphic Skull →

James Joseph Sylvester

James Joseph Sylvester was born in London to Jewish parents in 1814, just 201 years ago today. The family name was Joseph but, for reasons unclear, Sylvester – the name of an anti-Semitic Pope from the Roman period – was adopted later. [TM075; or search for “thatsmaths” at irishtimes.com ] Sylvester's mathematical talents became evident at … Continue reading James Joseph Sylvester →