Month: December 2018

On a ferry journey, Jude wanted a pen and paper game that we didn’t already know how to play, so she invented a variant on naughts and crosses (‘tic-tac-toe’). You play it on this board: You still have to get three of your marks in a row, but there are more ways for this to happen than in normal Os and Xs: Three rings: Three radial lines: Three clockwise spirals: Three anti-clockwise spirals: We wanted to know whether there was a winning strategy, so we drew a whole pile of diagrams to work out how the play would develop: and concluded that the first player always wins. Winning strategy for first player One winning starting move is for X to

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A friend kindly gave us some flashing-light stickers for Hallowe’en, and the natural thing to do with them once the festivities were over was to dissect them. So we did this, and found that each contained a square circuit board about 25mm on a side. When you press a little button in the middle, three coloured LEDs — red, green, blue — flash rapidly for about twenty seconds. It looked like they were flashing round in a circle, but too quickly for me to be sure of the sequence. To investigate, I set up the flasher approximately vertically, held in a lump of Blu-tack: Then I turned off the lights, pressed the flasher’s button, and took some pictures with a

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