OK, I deleted all these duplicates. How convenient for us they all used unique words; "Diophantine" is also good.
I guess we can thank their teacher for that courtesy!
Edit: wow, this is a much more serious problem than I realized. I count DOZENS (literally, dozens!) of accounts spamming us with the same bad python assignment questions. Two IP ranges, both map to Universities in India.
Laying down wide IP bans:
# incredibly abusive indian university homework, dozens of accounts
# spamming the same gratuituous homework questions
-A INPUT -s 188.8.131.52/16 -j DROP
-A INPUT -s 184.108.40.206/16 -j DROP
(specifically 220.127.116.11 and 18.104.22.168)
Also destroying many, many accounts.