All you have to do is pick up a baseball. It begs to you: throw me. If you took a year to design an object to hurl, you'd end up with that little spheroid small enough to nestle in your fingers but big enough to have some heft, lighter than a rock but heavier than a hunk of wood. Its even, neat stitching, laced into the leather's slippery white surface, gives your fingers a purchase. A baseball was made to throw. It's almost irresistible.