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The Japanese castles were nightingale floors
In Japanese castles and temples to a stranger was hard to sneak unnoticed, often installed so-called "nightingale floors". Floor boards nailed to a pole with nails in the form of an inverted letter V, which caused reminiscent of bird calls sound when the board is under pressure. And walking on tiptoes only enhances the effect, as the pressure on the ground in this case, was higher than that of full foot.
via factroom.ru
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