It always goes to say that the best things in life are free. I think in childhood the card board box is the most prized and timeless toy. The complete open ended toy. The wee beasties spent hours with this box.
Even the box came with warnings that the things in side were in deed fragile. Mama had one rule and one rule only that the occupant of the box must be sitting when the box was moving. Obviously rules were meant to be broken... Looking at the positive... No children were injured in the moving of the box.