Algodoo

An improvement to this would be making all the pieces' collideSet 0 by default, with no visual feedback to show if they're colliding or not. I forgot to click on the second piece that I tried to place, and it was one of the farthest away... disaster

Another way would be having a very high air friction to avoid pieces going to orbit the Sun...

Okay, finally finished! I wrote the last comment right when I started. Using max air friction multiplier and linear term is perfect

Thanks for the good suggestion.

Awwwwwww.... So cute! I love all bears, but Yogi is my favorite.

Okay, now for the bad news. You made a typo. (OMG!!!!).... In Note #2, "It's" should be "its".

And I have one suggestion: Make the "snap to grid" active so that the puzzle pieces self-align when they are very close to a grid coordinate.

Excellent puzzle. Definitely worthy of a ten.

EDIT: Please ignore my suggestion because I just realized that the pieces already do snap into place when they get clicked on and turn back to their original color.

Regarding it's and its, I knew the rule but somehow forgot to apply it (same thing with your and you're).

Regarding "snap to grid", I'm going to modify the code so that collideset=0 when the puzzle piece is moving and see how that works.

One word of friendly advice for you married guys...... NEVER, and I do mean NEVER correct your wife's spelling or grammar. To do such a thing would mean many long, cold nights of sleeping in the doghouse (take it from someone with lots of experience sleeping in the doghouse!).

Your statement implies that there are some subjects that you can correct your wife on. For me the list is very small ([]).