Hula hoops were all the rage in 1958. Yo-yos, popular before World War II, were relaunched in the 1960s. Rubik’s Cube, invented in 1974, quickly became a global craze. Sudoku, which had been around for years, was wildly popular when it started to appear in American and European newspapers in 2004.

## Archive for February, 2022

### Why Waffle when One Wordle Do?

Published February 24, 2022 Occasional ClosedTags: Algorithms, Recreational Maths

Where does new mathematics come from? The great French mathematician Henri Poincaré, a brilliant expositor of the scientific method, described how he grappled for months with an arcane problem in function theory. Exasperated by lack of progress, he went on vacation and forgot about the problem. But, as he was boarding a bus in Caen, the answer came to him in a flash. He was later able to return to his office and complete a proof of the result [TM229 or search for “thatsmaths” at irishtimes.com].

Continue reading ‘Sources and Scenes of Mathematical Inspiration’

### Where is the Sun?

Published February 10, 2022 Occasional ClosedTags: Astronomy, Spherical Trigonometry

*ecliptic*. The observer’s position on Earth is given by the geographic latitude and longitude. The path of the Sun depends on the latitude and the date, while the time when the Sun crosses the local meridian is determined by the longitude.

In his scientific best-seller, *A Brief History of Time, *Stephen Hawking remarked that every equation he included would halve sales of the book, so he put only one in it, Einstein’s equation relating mass and energy, *E *= *mc*^{2}. This cynical view is a disservice to science; we should realize that, far from being inimical, equations are our friends [TM228 or search for “thatsmaths” at irishtimes.com].