Rolling ball clock
A rolling ball clock is a clock which displays time by means of balls and rails. == History == The rolling ball clock was invented by Harley Mayenschein in the 1970s.
A rolling ball clock is a clock which displays time by means of balls and rails. == History == The rolling ball clock was invented by Harley Mayenschein in the 1970s.
A rolling ball clock is a clock which displays time by means of balls and rails. == History == The rolling ball clock was invented by Harley Mayenschein in the 1970s.
Source: Wikipedia "Rolling ball clock" · CC BY-SA 4.0
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