Diagram of two beams of light at different angles bouncing on a semi-reflective surface, and a drawing of a window behind a cylindrical fanning screen

Two beams of light bouncing off of a semi-reflective surface. They are at two angles so the one that bounces less is losing less brightness and the one that is bouncing more is losing brightness more quickly.A window with a screen in front of it. The screen is a half-cylinder shape and all the pieces are fanning out in front of the window. You can see some light peeking through the screen.