First of all, let's begin by saying...THIS IS NOT REAL CHOCOLATE! Sorry, hate to break it to you, but if you try to manipulate pentominoes or tetris-shaped pieces of real chocolate for very long, you're going to end up with chocolate sludge all over your fingers, and no more toy to play with. If you have real chocolate, EAT IT!
But if you've got Chocabloc, you've got a puzzle on your hands. Can you fit all the tetris and pentomino pieces together to fit in the tray? What other shapes can you create? Get a friend to make a shape and trace around it. Now can you create that same shape?
This would probably make a great Christmas gift for your favorite math teacher, too!