Light's On Application for Math Fair Brainteaser. Remember to record what you do! The Problem: There are seven lights in a circle. They are all turned off and the problem is to turn them on. Each light has a switch. The trouble is that the electrician didn't use proper switches. When you press a switch, if the light is on it turns off, and if a light is off it turns on as usual, however, it also does the same for the two lights on either side. Example. Turn on LIGHT B and LIGHT A and LIGHT C will corospond. TO USE: Click 1 Bulb and light the ones beside it.(They do not automaticly light yet) Good Luck! and NO CHEATING! P.S: To find the original problem go to http://www.galileo.org/math/puzzles/LightsOn.html