My daughter needed to do some stretching for physical therapy so I did the stretches with her and I got tired of counting so I made this app. The result was actually better than I expected because it freed us to talk and laugh while doing the exercises.
It's probably the simplest app I've ever created but you might find it useful if you stretch.
https://play.google.com/store/apps/details?id=com.mcgintech.stretchtimer