Jo
Cheap hotel carpet. The whole category. I keep trying to find a second member and there isn't one — nothing else has that specific pattern-designed-to-hide-thirty-years-of-stains thing going on. Maroon and gold swirls, or that weird geometric puke-green thing, like someone asked a carpet to actively lie to you.
I stayed in a place outside Leeds once, business trip, and the carpet in the hallway had cigarette burns arranged almost decoratively, like they'd given up hiding them and started incorporating them. That's the category. Just that. I've tried to put airport carpet in with it and it doesn't fit — airport carpet is trying to be inoffensive, cheap hotel carpet is trying to actively deceive you about what's happened on it.