Attempt at creating an arc that doesn't really look like the eye of sauron but rotates to follow the mouse position. Similar to my follow javascript. You can the rotation with canvas with CSS, and if it's a square it'll still look fine and should render more quickly than if you redraw the canvas to rotate the drawing of the image. You can capture the original canvas in an image and store it and then insert it into a canvas as a new image.
moved to jquery-follow-cursor
middle:
mouse:
adjusted:
pure angle:
angle:
quadrant: