Here is a peek at a draft Mobius Strip script.

Loft, Not Closed, works well, but leaves a gap.
Hide or erase the lines, and do G2 blend of the gap, then Boolean union.

(A closed Loft seems to be much faster, but messes up the closing of the gap.)

(Mobius strips have been done on the forum before.)

I want to try a few more things, including concentrating the twist, or "fold," to limited areas of the band length.
And maybe add some thickness?

By doing a 0.2 offset, and another 0.2 offset flipped, a trefoil Mobius band can be made.

- Brian