Getting weird with it today! Not sure whether to call this a 21x21, a 2x2x10x10, or something else entirely. Also not sure if it really counts as a meta, but if you want it to then that's fine by me! Won't say anything more to avoid spoilers. Thanks to Paolo for the test-solve!
I don't recommend the pdf unless you have perfect eyesight, but grab it here if you want; the puz file is here, and you can find the interactive client below. Happy solving!