matthen:The Cycloid [red] is generated by tracing a point on a rolling circle. This animation shows
![matthen:The Cycloid [red] is generated by tracing a point on a rolling circle. This animation shows](https://64.media.tumblr.com/tumblr_mdw9702y5m1qfg7o3o1_400.gif "matthen:The Cycloid [red] is generated by tracing a point on a rolling circle. This animation shows")
matthen:The Cycloid [red] is generated by tracing a point on a rolling circle. This animation shows a curious symmetry between the Cycloid and itself shifted. The traced lines are always crossing at right angles to the top cycloid and are tangent to the bottom. [The Cycloid is its own evolute] [code] [more] -- source link