The Formula t-shirt by Insanely Great Tees

Like we could help ourselves from posting this. Coffee is the wellspring from which all creative thought–nay, even civilization itself!–flows.

It appears to be printed on something greyish-green or greenish-grey, depending on which pic you look at. You can see for yourself on the Insanely Great Tees site here.

Found via Shirtlog.

P.S. Just remember: decaf kills.