1. We live in a three-dimensional world. Our hands are designed for moving and rotating objects in three dimensions, for picking up objects and placing them over, under, beside, and inside each other. No creature on earth has a dexterity that compares to ours.

    The next time you make a sandwich, pay attention to your hands. Seriously! Notice the myriad little tricks your fingers have for manipulating the ingredients and the utensils and all the other objects involved in this enterprise. Then compare your experience to sliding around Pictures Under Glass….