A lightbulb.
A: I don't waste my time with these childish jokes.
One for the money, two for the show.
A: The Outside.
The porcupine's pricks are on the outside.
With the hedgehog the pricks can be seen on the outside and with a Jeep the prick can be seen on the inside.
A cardboard box isn't always empty on the inside. :(
