- I have no idea if this elegant counterexample is the same counterexample or just a counterexample that exploits the same key ideas - many of which seem to have been developed earlier by Vithuskhin, btw:
https://gist.github.com/littledivy/521aee9397d7e92a4b6e4202e2c984c0
It might be "the same" after some clever changes of coordinates! But I don't know.