Arrow L/R : Rotate Space : Hide / Show UI R : Render the circle is draggable double click the circle to restore the default position [refresh rate] milliseconds [reflection] desides how many times does the photon reflects [resolution] is the length of each step around the edge (smaller means more acculate)
*1~3 are the recommended [resolution] value. The process slows down as the value is reduced. inspired by https://www.youtube.com/watch?v=jJ6FD59U0_E