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#15 Lines through the chessboard

Linus is using a thin felt-tip pen and a ruler to draw straight lines on a conventional 8脳8 chessboard. With eight lines, he can easily ensure that a line passes through every square on the board. For instance, he can just draw a line through the middle of each row of squares, which means each line would go through eight squares. But a line can pass through more than eight squares 鈥� for example, the one in the illustration goes through nine 鈥� so Linus wants to find a way to cut through all 64 squares with fewer than eight lines. Can you help?

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#14 The H coins problem

Solution

Add two coins to seven coins that are in an H configuration to make 10 lines of three like this:

(There is a third solution, which is just a mirror image of the second solution.)

Quick Quiz #14

1 Which area of the brain鈥檚 frontal lobe, crucial for language processing, is named after a 19th-century French anatomist who studied speech impediments?

2 鈥淪pukhafte Fernwirkung鈥� 鈥� whose phrase, about what?

3 The red veil of St Agatha supposedly saved the city of Catania from the advancing lava of which volcano?

4 The American alligator takes its formal name from which US river?

5 Which moon of Saturn is famed for the icy geysers shooting from near its south pole?

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