Have you tried playing with a rotating chair? Once you start rotating it with your hands close to your body, it will rotate fast.
While you held your hand straightforward, the rotation speed becomes slower because of the changes of angular momentum.
On the screen, the square indicates the body, the circle and triangle represent the arm.
The arm length can be manipulated by scrolling the mouse wheel.
When you manipulate the arm length, its angular velocity will change according to its change of angular momentum.
Angular speed will be accelerated by clicking the left cursor.