I want to turn a motor at 39 deg/sec then slow to 22 deg/sec then back to 39.  Twelve times in one rotation.

I'm struggling to get a simple model to change speed in a predictable fashion.

The plan is to then add to a complex model and possibly accel and decel.

The setup below does start fast, then slows and then speeds up. However the it slows after a couple of degrees then speeds up after a few degrees.