I used to do a lot of jigsaw puzzles a few years back, then I discovered jigsaw puzzles online.
I remember one my Mom got me for Christmas one year. It was round and the picture of green marble. That was my first round puzzle and wasn't sure how to attack it since other pieces had round edges.
I got very interested in 3D puzzles. The hardest one was the Eternal Woman. Each piece was a flat contoured disk and you had to fit each on a spindle. You start at the neck and work upwards. Here's an assembled picture:
https://www.ebay.com/itm/265330094749
The largest jigsaw I have ever done was 1500 pieces.
EDIT: After finishing the neck of the Eternal Woman, I took a step back and realized that the muscles didn't look right. I started taking it apart when a piece fell on the floor backside up. That's when I discovered the pieces were number in a very faded blue, kinda hard to see at a glance. Each piece was marked to indicate frontside up.
Music is the Heartbeat of the World
Let's flip a coin; heads I win, tails you lose. Fair enough?