Circular health bar.

Hi I have been able to make a typical square health bar using the GUI just fine. However I would like to make a health bar that curves in the shape of a 1/4 a circle. That way I can have my char's face in the middle of the circle and have the health curve around it. not sure on how to start though any ideas?

Use search before posting a new question. This has been explained in detail by Eric5h5 here. Good luck.