My partner publishes crosswords and it's always fun to see how much artistry goes into authoring a puzzle. You can play with the structure/grid, the theme of course, every minute detail of the fill, etc.

Never would have thought of a Mobius-strip though, insane.

It's crazy how good puzzle creators are. I've watched a bunch of videos on it and I'm still in awe of how effortless they make it seem.