re:Deacon
Sorry to double post, but... I mean, given Hussie's simplistic style, I would say the exact kind of top Karkat is wearing is pretty up to interpretation. The only thing that technically changed is that some fan-contributions depict it as having a turtle neck, but I don't think Hussie would draw a long-sleeved t-shirt any different from a plain old crew neck sweater.
I doubt hussie himself even remembers if it was a t-shirt or a sweater. Dave went from wearing a short-sleeve t-shirt to a long-sleeved one, with red collar and sleeves. And that happened without fan contributions!