Can you solve it? The joy of grids

Alex Bellos’s Monday puzzle Dot-to-dot puzzles that hit the spot Part of the poster for TRON, the joyous 1982 film set in a grid.Photograph: Everett Collection / Rex Feature Hi guzzlers, Today, three challenges using this grid of 16 dots: 1. A polygon is a shape where each side is made from a straight line.…

Detecting tsunamis

Credit: Cardiff University Mathematicians have devised a way of calculating the size of a tsunami and its destructive force well in advance of it making landfall by measuring fast-moving underwater sound waves, opening up the possibility of a real-time early warning system. The sound waves, known as acoustic gravity waves (AGWs), are naturally occurring and…

Learning through play is plane easy | Letters

Lin Friend on getting her early-years class to play airports; maths is fun, says Karl Sabbagh Children playing pure mathematics, alias chess, with Russian grandmaster and former world champion Garry Kasparov. Photograph: Xinhua/Barcroft Images I was an early years teacher for most of my career (Letters, 16 January). One afternoon our new head who was…