Classic Example - Enzo Mari Animal puzzles. I can remember playing with these at a very young age, and still have them somewhere.
Lots of play value here, as it is both a puzzle and a set of characters for imaginative play. Comes in a wooden box for easy storage, which I've been told is an important feature which a lot of parents look for.
This one is pretty advanced. I would definitely buy it for a child. Great idea thanks:)