Excuse my noobness, what is a pencil mod?

I happened upon a pencil mod thread here for the 8800gt. It had pics etc, think it was to increase the GPU voltage.

So, what is a pencil mod mean? I know it is changing a resistor on a board to give a diff value resulting in a voltage change.

Why is it named pencil mod? Graphite?

It interests me greatly, once I get the TRight cooler for my 8800gt I want to OC, and maybe the pencil mod will give me a bit more headromm. I like headroom, hehe.

Noob out...............

There was a mod for the old AMD CPUs where you could draw lines on the chip with a graphite pencil to connect a few spots together to unlock the multiplier.

You cover the resistors with the pencil, the graphite then bypasses the resistor therefor increasing the voltage