In which ZUN accidentally the GRCG rather than the EGC in what should
have been (?) the unblitting function. Which then ends up actually
blitting yet another randomly background-masked version of the same
sprite on top of the old one. And after just a few frames, you get
those fully filled red diamonds you don't see in the sprite sheet.
Then again, if the 16w×h rectangle unblitting function is all you
have, and you can't be bothered to actually learn the EGC, this *is*
the better option 🎺
Completes P0120, funded by Yanga.