Here's another one of Sheldon's sorta-plain t-shirts. As with most shirts of these types, finding it online (or even knowing what to look for description-wise) is a pain, and feels nearly impossible. With that being said, it was possible for this tee. It originated at Urban Outfitters once upon a time. For now, unfortunately, it's location is a mystery to us all.
Featured on The Big Bang Theory Episodes
S01 E02: "The Big Bran Hypothesis"
S01 E08: "The Grasshopper Experiment"
S02 E13: "The Friendship Algorithm"
S04 E06: "The Irish Pub Formulation"
S06 E02: "The Decoupling Fluctuation"