# Boolean Logic to the tune of Who Let The Dogs Out

Boolean logic is the mathematics used to build computers out of simple elements. It turns out that one only needs a single kind of element to do everything! That element is called a NOR gate, and the goal of this page is to give you an understanding of how a NOR gate works.

Consider the analogy of the song WHO LET THE DOGS OUT?

Someone let the dogs out of the house!

OR gate Suppose the house has two doors - one in front and one in back. If either the front OR the back door is open, the dogs get out. Shame on you!

AND gate If the house has instead an anteroom, you have to leave both the inner AND the outer doors open to let the dogs out.

NOT gate To make a NOT gate, we put a trap door in front of an open door that leads out of the house. When the trap door is closed, the dogs get out. When the trap door is open, the dogs fall into the trap. We put nice soft stuff for the dogs to land on and we have the trap lead back to the inside of the house. (This web site will never harm imaginary electroic boolean dogs!) The dogs like jumping into the trap and running back up the ramp into the house, so if the trap closes, they can run outside.

Connections To make a computer we have to connect gates together. I'm not entirely sure how to do this with the dogs, but suppose that when the dogs come to a door, they must pull on a rope to get a snack! The rope is connected to doors elsewhere maybe not even in the same house, so dogs running around in one place can let dogs out (or not) in another.

NOR gate A NOR gate is an OR followed by a NOT gate. NOR is a bit harder and I didn't see how to explain that easily yet.

But given NOR one can build any computer! So our molecular computer patent is about how to build a NOR out of molecules - which means one can build any computer that way! ...

The Cartoon Guide to the Computer by Larry Gonick and Mark Wheelis is an excellent introduction to Boolean logic. If you read it carefully you will know how to build a computer!

Music: Who Let The Dogs Out by Baha Men (the original source of the midi is gone.)

Schneider Lab

origin: 2004 March 22
updated: 2014 Nov 10