Idea for calculating position/angle?

[Mudbill]

I guess you could say that. I have a little Youtube experimental series where I take ideas and try to implement them, though I have a certain line I want to follow. This exact situation is present in a puzzle I'm making involving guiding a beam of light using mirrors, lenses (for colors), splitters and other contraptions. The reason I need different angles is because the player should be able to place these objects differently, since each check point can have 4 different results based on angle of each object.

Here's a video showing it more in action. Perhaps it can help explain the issue better. Skip to 6:00.
[video=youtube]http://youtu.be/yc48CqOc-qU?t=6m[/video]