What does it do? It gives haptic feedback (vibration, flash, or both, with different strokes for different folks) to people who need stimulation.
How it looks: The size depends on the type of widget.
Here are a few proposals:
Spring loaded slider - size from 1×2 to 1×5 (vertical or horizontal depending on the user resize of the widget). The slider moves freely under the finger but springs back to one of the slot positions. Every time it does, the haptic feedback is triggered.
Soap bar: As above, it has spring-loaded positions, but this time, it has a 3×2 grid, so the user has two degrees of freedom.
The scrolling wheel is like the one in the glyph timer, but it has a spring-back lock at every, let’s say 15-degree angle. The widget comes in two sizes: one is the same as the glyph timer, and the other is smaller and requires a smaller finger movement.
Spinner: This is the same as the above, but it has a much lower spring that locks into a position that maintains movement inertia.
Rolling ball - a channel (pipe) or any other shape like a square or rectangle (could be a maze). A ball rolls within it based on the phone’s motion sensor. When the ball stops its movement on the wall (end of the pipe), the haptic feedback is triggered. In connection with the maze shape, it could be the next community game widget, but that’s another idea.
Buttons and switches - a single switch and a single button that can be switched or pressed for haptic feedback.
And many more. I gave a few examples based on simple on/off states, but with the PWM of the vibrator, much more sophisticated fidgets can be created.