What did Chinatsu make?
It's likely a nod to how terrible of an artist she actually is.  That is, when she tries to be good.

Earlier in the same episode, she was reading off a picture book to the group.  At the very least, it freaked Yui and Kyouko out a ton.



The likely inference here is that her art sculpture is so bad, that censoring it is the only sane way to show it to the rest of the world.