Genady

An overview here is very interesting (but doesn't include the encounter described in OP): North Sentinel Island: a timeline of the world’s most isolated tribe | Atlas & Boots (atlasandboots.com) PS. Perhaps a good model for humanity if we are ever visited by aliens.

Susskind said in one of his lectures something like, "Who knows what Heisenberg was smoking when he came up with the matrix mechanics."

Correct. (which was the Einstein's interpretation)

His interpretation was hidden variables. Bell came up with the test, after Einstein's death. The test refuted Einstein's interpretation.

Sure. Einstein.

Isn't it the Copenhagen interpretation? Then it's Copenhagen (for me). The non-Copenhagen interpretations seem to try to adjust QM to our classical intuition. It seems to me easier to adjust the intuition to QM.

Then it's Copenhagen (for me). Honestly, I don't understand this reference. Could you explain?

Yep. And proud of it

I don't know. I don't have one.

With so many, how does one pick a favorite?

So, you mean in your OP, "we can intuitively distinguish intuitively wrong from intuitively right definitions"? Also, if they follow from axioms, then they are theorems rather than definitions.

How are they proven without definitions?

If we assume that the "optimum" means maximum amount of light on the wall, and if we stick with the sketched configuration, then I believe my equation above is the answer.

How? Your examples didn't make it clear to me.

Right. OTOH, if it were like in the picture - just as a fantasy - all that would be needed is a flat sheet of aluminum foil curved into a cylinder. Of course, a flat surface like in your earlier post would do, too.

Yes, there really are.

I think it scared them.

No, I mean I don't believe it's a practical problem. Regardless, I gave you the equation above that solves the problem. Is it unsatisfactory? Where in the world the sunlight comes vertically like in the picture? How often does it happen and how long does it last?

I don't believe it.

Another answer is the attitude of my father-in-law, in his words, "Do it and it will be done."

If I've guessed correctly which angle, then you get the equation 0.5*sin(x)+(0.5-0.5*cos(x))*tan(2x-π/2))=5 OTOH, it can be as small as 0.

0.5 factorial?

Radius/diameter can be anything between 0 and infinity.

Optimum what?

I don't know about an ecological importance of freshwater mussels, but I have witnessed how instrumental they were in recovering of a popular SCUBA diving spot in PA, USA, called Dutch Springs. It is an old, abandoned quarry filled up by fresh water naturally. The water was getting more and more cloudy every year until the visibility was practically 0. Then the management introduced freshwater mussels one late fall as the quarry closed for the winter. By next spring when the quarry opened again for visitors, the water was clear with the visibility in tens of meters. Pretty much everything underwater was covered with a mat of mussels, but nobody cared. There suddenly was a lot of light and colors, fish, seaweed, rocks, wrecks, etc.