| 
    
    
The cycloid is the evolute of an identical cycloid
.
This means that if a thread supporting a weight is forced to move
 along a cycloid, then the weight
  supported by the thread describes another cycloid.
 
However, because the time a body
 takes to reach point A on the cycloid is independent from its starting point,
 (tautochron curve ),it follows that the period
 of suspension is independent from the amplitude of oscillation.
 
The exhibit shows the difference between a cycloidal pendulum,
which is perfectly isochronic, and an ordinary pendulum.
     |