This site provides an activity on reflection using just three mirrors and duct tape.  A kaleidoscope effect is produced to show multiple images of an object, and a corner mirror is created to demonstrate a reflector that always sends light back in the direction from which it came.  The site also contains an explanation of the physics involved, provides several extension activities, and includes a math lesson. Materials needed and assembly instructions are also given. This activity is part of Exploratorium's Science Snacks series.