Sudanese Mobius Band

I remixed this from the model by stepanp21, https://www.thingiverse.com/thing:1779983.
"...the Sudanese Möbius Band, where 'sudanese' refers not to the country Sudan, but to the names of two topologists, Sue Goodman and Daniel Asimov."

I smoothed it in one model and added a flat base in the other.
The area near the bottom can be difficult to print unless you use some support and fine layers. I used minimal support inside to get the crossover without sag. It can be hard to remove, so keep