The Simply Impossible Puzzle

This is a deceptively difficult puzzle to solve.

A quick look and you will think this thing belongs in the kids section of the toy store -- a three-year-old would have a great time with this

... then you pick it up and begin to play ...

Whoa! It turns out this puzzle is difficult. Quite difficult! The pieces don't fit together the way you think they might. Give it a try. It's fun!

You will need to print four pieces to make the puzzle. I prefer to print them one at a time switching filament for better color.

##Version 2
With just a couple of minimal tweeks, version 2, is greatly improved compared to the original I posted in December 2022. It's a bit harder now, and has become more difficult to cheat it.

1. I narrowed the gaps to .5mm based on the awesome suggestion by @Xanthopteryx. So it is less likely to accidentally crumble apart in your lap, and it simply looks better -- more like a real jigsaw -- when assembled.
2. I added a tiny space on the flats between