system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 how double toggle switches work.

*Note: I'm not sure if they have a name/what their name it is but I tried to make it as obvious as possible.*

What I'm talking about is when a light has two switches and both have the ability to switch the light from off to on and on to off. It can't be as simple as two circuit breakers, because if one was in the off position, the other would be useless. 

This problem has troubled me for a while now.
gpt
They use two wires.

Here the two are switched the same way, so there's a connection and current flows (through the top wire).

            ______________
    _______/              \_______
            ______________

If you flip either of them you end up with this:

            ______________
    _______               \_______
           \______________

or this

            ______________
    _______/               _______
            ______________/


Both of which break the connection.

But then if you flip the other one you get this


            ______________
    _______                _______
           \______________/


And there's a connection again (through the bottom wire) so the light comes on again.

Whatever the set-up, flicking either switch turns the light off if it's on, and on if it's off.