Speed Control and Pause Button

> Lovely animations. For teaching purposes I'd really appreciate a speed control and a pause.

> It’s awesome and really nicely designed. Is there a way to slow it down? I’d even do that in the source code I just don’t know which file. Thanks

Maybe just a speed scroll can solve , this was a common reported feature request. (Zero value from speed could be used as "pause" (or even rewind!))