Today Sean asked for something tougher than my normal jigsaw puzzles, so I found an abstract picture of cubes.
I almost made all of the pieces square, but since working a test version of it, and taking twice as long as normal, I decided against that. You can thank me later.
Enjoy!

Beginner     Easy     Medium     Hard     Tough     Extra Tough  
 

In case today's jigsaw puzzle is too tough, or even not tough enough, here's an extra one from a few years ago called Abstract Faces.