Graphite.

It's a problem with the graphite, sir.

OK, now, these are my sprinting legs, made of carbon graphite,

This right here is carbon, and this is in the...in its graphite form

Here. On one side, you have mercuric oxide and graphite from your brake pads.

Then with a brush I smudge the graphite for a more even finish. I reinforce the shadow in the vicinity of the drop, and then smudge it.

They're both made of carbon, and yet one of them has carbon atoms in it that are arranged in one particular way on the left and you get graphite, which is soft and dark.

And I'm up there in Boston against people wearing legs made of all things carbon graphite and, you know, shock absorbers in them and all sorts of things and they're all looking at me like,

One of the materials that can do this is a remarkable material, carbon, that has changed its form in this incredibly beautiful reaction where graphite is blasted by a vapor, and when the vaporized carbon condenses, it condenses back into a different form chickenwire rolled up.

I am of course quoting from a famous essay by Leonard Read, the economist in the 1950s, called I, Pencil in which he wrote about how a pencil came to be made, and how nobody knows even how to make a pencil, because the people who assemble it don't know how to mine graphite, and they don't know how to fell trees and that kind of thing.