You might have noticed in the last couple pages that Jackson has tattoos! The bottom part of the sleeve is based on the molecular formula for kevlar. It’s not exact, but I wasn’t about to draw a bunch of Os and Ns and Hs in there.

The middle part that’s half covered by his shirt sleeve is strands of DNA. You can’t see the top but there’s a giant diagram of an atom on his shoulder. On his other shoulder Jackson has a Marine bomb squad thing.

There’s close ups of all that in the book, if you wanted a better look.