A tennis ball has both information in its spin and momentum in its velocity, and you can feel the translations of information and entropy when you hit a ball with topspin or a ball with backspin. You can also feel the energy required to impart spin in the extreme hand-speed required to hit a ball with significant topspin. While not fundamental information, ball spin is a kind of quantised meta-data that is made from the velocities of the constituent particles in the way that a phonon is a composite bit of information made up of the momentum of its constituent particles. Quantisation isn’t small.
It is very hard to hit the ball with varying rates of spin. Once you learn the techniques, your topspin will be pretty consistent and your backspin will be pretty consistent, in the same way that a baseball pitcher’s curveball will break pretty consistently. These rates are existential, not specific to the shot or pitch. You might have two different spin shots, a driven slice and a defensive slice or a curveball and a slider, but not a continuously variable spin rate. This part of the game is quantised.
One of the great problems in modern civilisation is that tasks are quantised, while solutions are not. Success and responsibilities go to those people who can perform the most tasks in the least time, and for a while their accomplishments look like solutions. But then the entropy mounts up and nobody with the least bit of power has the slightest idea what is happening or why, so they complete even more tasks in even less time. The people who can see the big picture, that tasks are just one part of the game, are marginalised. When I first saw Nadal play I thought he wouldn’t go very far with that extreme topspin game because the spin is so predictably two-dimensional. But Rafael Nadal isn’t great because he has topspin. Nobody has adopted his style with any success. He is great because of the way he adds it to the momentum and placement of the ball, and because of his own movement and mental strength.