Never heard of Trajan? I guess you're not a graphic designer. But you've definitely seen it: it's everywhere, on every other movie poster you've ever seen. My wife works for a movie poster design firm, and sometimes when we drive around LA, which has way more movie poster billboards per block than any other city (because movie executives like to see posters of their movies around) I'll often hear her scream "AGGGH! TRAJAN!" at some passing sign. That's how sick of it she is.
So what's Trajan, and where have you seen it before? This video from Kirby Ferguson explains it all, and rather hilariously.