I'm playing on an iMac; when I get to the part where you unscramble the…

I'm playing on an iMac; when I get to the part where you unscramble the blocks to break free from the hypnotic powers and restore vision -- the pieces I'm moving are in a different scale than the background (smaller)... I get them unscrambled to form the picture, but the pieces don't "fit" since they are the wrong size -- anyone else? Fix?