They all do this...
Imagine your old school tape recorder in a petite handmade wooden box. Add a knob so you can speed up your recording or slow it down (Alvin and Chimpmonks to Barry White). That's it. Simple right?
But wait, there's more
Not to complicate matters, but add a switch, you know the switch in movies they tell you not to touch. I'm suggesting you toogle that switch so your recording plays on a contiuous loop for endless fun.