//Step - then step again theta = theta+3.1416 / 40; //angle to rotate yb = Math.sin(theta)*r; xb = Math.cos(theta)*r; Move(blueball,xb,yb);
//Reset - runs just once r=1; theta=0;

Click reset, then run.   You will see the blob run around in a circle.

Want to try something more adventurous?

Edit the code in the upper window
to make the blob spiral in to the centre
Now try for the ABC logo.