The first time you try using this program ,it could be confusing , but once u get started its smooth sailing.
Follow the following steps :
1) Create a light beam
2) Move it by dragging the beam source
3) Rotate it by clicking the mouse on the ends of the beam source
4) Add a couple of plane mirrors
5) Rotate and move the plane mirrors like the light beam
6) Experiment !!
1) Avoid trapping light in mirrors as it may cause system to crash
2) Increased Iterations can cause system to crash
3) Lowering opacity helps visibilty of ray over lap
4) Use shades to isolate regions
5) Run Program in full screen for better experience