The modern electric traffic lights were invented by William Potts of Detroit Police Department. In fact, he adapted the railroad lights for street use – in this system red, yellow, and green meant "stop", "caution", and "all clear" respectively.
The largest diamond ever found was the Cullinan diamond of 3106 carats (one carat is equal to 0.20 grams). It was cut into 105 diamonds.
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