Why does this light bulb shines? 

Lamp/Lamp

Lamp/Lamp

Lamp/Lamp is a light bulb.
How comes it shines without using the socket?

In Lamp/Lamp there are two sockets.

In common light bulbs, when you use it the socket is not visible.

This is a simple idea of "having two sockets attached". Just with that, a mysterious atmosphere is born.

12 at random.