Select the constant controller at bottom left and change the value of the constant, a, and observe the transformations. Also if you select OPTIONS and choose animation up/down and set values say -360 to 360, steps of 5, click ok and press play. Furthermore, use the left mouse to move the centre (origin) and observe. Note: Positive 30 means anticlockwise rotation, -90 means clockwise.
Enjoy!

If you make any errors, start again! You can use the pen in class discussions.
You may need to download Autograph Player (Link at bottom of this page).