when I fit in, but didn`t belong

The purple piece had edges where the other pieces fit

And rounded parts and corners to help them out a bit

The left side found a partner with a piece that fit too tight

The bottom edge made do with one that wasn't shaped quite right

The upper made a sorry match that bent it out of whack

The right side tried to fit so much it nearly broke in half

Now you may not even recognize that purple piece you knew

It fits so well, all squished and bent

Except

The puzzle's blue.