That’s boring. Two ears only allow you to put the sound somewhere on a plane (the vertical one that cuts your body in half lengthwise). How do you know the ‘height’ of the sound on that plane? By utilizing the different distortions the sound goes through while being funneled through your auricle.

Read somewhere that catching is actually dead simple, just "move towards the image of the incoming target" (I'm not talking about the arm kinematics).

There were a robot paper bin that zoomed under stuff you threw up in the air using no complicated algorithms for example.

Funnily many algos are calked on physical and chemical effects in the real workld, like splines for example were made with a thin metal bar and lead weight bending it to get the lines used in boat hull construction.

If the earth were shrank down to the size of a golf ball, you could feel houses.

We have equipment to measure down to microns, and my students often test how fine details they can feel.

I mean, most people do it across, rather than along the blade, what with the necessity of detecting a burr, which can't usually be felt length wise. You slide along the blade, and it is sharp, if you screw up you get cut.

That doesn't take away from what you're saying, it's very true, no matter which direction you're feeling. Just normal, average fingertips can pick up stuff like that, that you'd need a microscope to see. It's a trip!