Jigsaw Ugly 4

Description from the creator's website:

Jigsaw Ugly4, what is so special about these puzzles?   
Whatever we tell you, we'll reveal the magic to you ... and that's why we'll let you enjoy the magic yourself.

Okay, let's talk a little about them though.
These puzzles are called ugly4 because the real fun starts when the player puts everything together except the last 4 puzzles.

Put together all the way to the last 4 puzzles and it's not that difficult and you will very likely think that this is an easy puzzle. But the last 4 puzzles put you in front of a special problem and I will just say that one of my friends struggled with that 4 puzzle a full 2 hours before he gave up.