It's pretty clean, isn't it? There is certainly no plaid there. And it makes a mockery of Upperpunk's ridiculous claims about his shirt pattern matching Lovelady's.
The idea that he had lines corresponding to Lovelady's is ridiculous, and it's even more ridiculous to say that the lines would be diagonal. He wasn't leaning over. He was just standing there like a normal person. This is Oswald:
And notice that in Wiegman, he didn't have any plaid either.