ParamPlot

Play
The most important button. The curve is displayed when hit.
Frame Advance
The Frame Advance advances the curve frame by frame. The Frame Advance button will not work if there is that phrase "No more frames."

Direction
The Direction button allows the image to be drawn either in a forward direction or in a reverse direction.
Playback Mode
The Playback Mode allows single play if the icon is a straight arrow. If the icon is shaped like a loop, the Playback Mode allows continuous play.