This wiring diagram illustrates the connection for a 3-way switch setup used to control multiple lights from two different locations. The diagram includes the wiring arrangement for the lights, the two 3-way switches, and the power source. Each 3-way switch has three terminals: one common terminal and two traveler terminals. The common terminal is connected to the power source, while the traveler terminals are used to connect the switches together. When one switch is flipped, it changes the state of the circuit, either connecting or disconnecting the power to the lights. The second switch then allows the user to change the state again, controlling the lights from a different location.