| Rectangular Prism: The rectangular prism refracts and partially reflects incident light. Place one or two rectangular prisms anywhere in the simulation window. With Select depressed, you can move, resize, and rotate the rectangular prism. You may place point light sources and beam projectors within the prism. You can also change the width and height of the rectangular prism using its Properties Box. In the Properties Box, you can also select the medium within the prism: air, water (default), glass, or diamond. The Properties Box lists the refractive index of each medium.