Have you tested any of your claims? https://go.dev/play/p/596Wj16Phzj

How?

The newWord variable isn't needed.
The explicit cast also isn't needed, and it is implicit from the defined return type.

The contents of the string is irrelevant.

Apparently, this can be done in O(n²) at best. Correct?

Done. If you still have troubles, make sure you're using 3.8

Best solution out there! Very elegant!

I'll try to figure out anyway, but I agree with you.

Could you please explain the logic behind the choice of 0.0002?

Yep. I was misled by its behavior because of the iterator's name.

So elegant and simple. Amazing!

Equivalent to iter_s = iter(s); zip(iter_s, iter_s) or zip(s[::2], s[1::2])