I'd guess the shape is an ellipse. I remember learning way back in geometry that...

		Zaheer on Sept 21, 2013 \| parent \| context \| favorite \| on: Ingenious Designs That Will Fool Your Eyes I'd guess the shape is an ellipse. I remember learning way back in geometry that ellipses have special reflective properties: http://www.math.ubc.ca/~cass/courses/m309-01a/dawson/