well I have been doing electrical the all this week so I figured I would post about one of the most confusing concepts for an amateur electrician.Yes the 3-way switch. Rather than go into great detail about them I will just post 8 diagrams that are invaluable to have. It will make your next project a whole lot easier. These diagrams do not show retards tapping into the lines or the use of old 2-way lines converted to 3 way, so if you have more wires than this get a notepad out draw a diagram and use your brain and think about it. Ohh and remember TURN THE POWER OFF WHEN WORKING ON ELECTRICITY! Have fun and enjoy! All stairways have them, one at the top one at the bottom to control the same light.