I purposefully slightly tilt most my wall hangings. I like watching guests squirm when they mention it and I do nothing

See, I live in an old apartment. The corners aren't 90°, the wall a picture is hanging on is convex. When I'm lying in bed and look at the picture it looks like it's crooked but I used a level several times on it and it's as straight as can be. It's driving me insane.

I worked on an industrial robot once, and we parked it such that the middle section of the arm was up above the robot and supposed to be level. I could tell from 50 feet away and a glance that it wasn't, so we checked. It was off by literally 1 degree.

Degrees are bigger than we think, but also our eyes are incredible instruments.

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

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!

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

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.

My hearing is pretty severely damaged in my left ear, and for several months I thought everything was to my right. but my ability to locate sounds has come back. My hearings not any better, my brain just figured out that my left ears fucked and compensated.

I got into an argument with someone once about this, when they told me (paraphrasing) "it's safe to drive listening to music through headphones, because they let outside sound in".

Yes they indeed might, but - even ignoring delay introduced from digital electronics - you've now lost all sense of where that sound is coming from, because you're listening to the sound of one microphone being played through one speaker.

The human ear really is an incredible thing.

I think the “more to it” might be significantly crazier than the timing thing.

Or ears have unique complex shapes that attenuate certain frequencies and bounce sound around in complex ways depending on the direction they are coming from. And our brains instantly process all that stuff too. It’s why our sense of hearing isn’t just on a flat plane around our head.

What's amazing is our ability to calculate the path of something in the air.

There's a test they did with Cristiano Ronaldo where someone kicked a ball to him so he could head it. They shut off the lights before the ball was in the air and somehow from the body shape of the person kicking it, he was able to know how to make contact with it without being able to see it.

https://youtu.be/0k2ey_okQ4E?t=1255

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.

I remember when I was younger and would lay on my back throwing a baseball up in the air and catching it, that I could watch it go up and not follow it with my eyes as it goes down and still have my hand in the right spot to catch it

Or tiny birds that can expertly navigate wind currents with an almond sized brain using real-time force feedback. The computational power at their disposal is very well optimized for what they do.

Yeah there is a lot of neural networks, but i don't think that is the only thing in brain. There could be calculators and integrator circuits