A square window let in too much light. He blocked half of it — and it was still square
A man had a window that was a yard square, and it let in too much light. He blocked up exactly half of the glass, and the window was still a yard high and a yard wide, and still perfectly square. How did he do it?
Reveal the answer
He turned it into a diamond. A smaller square, rotated 45 degrees with its four corners touching the midpoints of the original window's sides, has exactly half the area of the original, yet measured from one corner to the opposite corner, it still spans a full yard in height and a full yard in width. Henry Dudeney set this as puzzle no. 205 in his posthumous 1932 collection, 'Puzzles and Curious Problems.'
— Henry Ernest Dudeney, Puzzles and Curious Problems — 1932, puzzle no. 205 (also no. 271 in the 1968 compilation '536 Puzzles & Curious Problems')
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