Unfortunately, copyright is purposefully designed so that most works going into the public domain are irrelevant by then and nobody's willing to convert them.
If the photocell is pointed east, weather does make a big difference. For other bearings, less so. And light pollution is more or less the same every night so it can be accounted for. Still, I suggested an LCD alarm clock as a decent compromise between accuracy, feature set, cost and transistor count. An analog one has fewer, closer to a 555, but will use more energy and produce a ticking sound (still less than the computers' fans). And then there's a windup one or a rooster...
I like how you two think, reducing the required transistor count from tens of billions (mostly DRAM bits) to 26 to zero.
(For the daytime question, personally I'd use a photocell to measure sunlight, one transistor to amplify the signal, another to switch based on a threshold, and a third as an oscillator driving a 3-pin piezzo buzzer at its natural frequency. No more semiconductors required. Nowadays, an LCD digital alarm clock from a dollar store is a potentially cheaper, silently running solution. It also shows time with an update every second that does not send 120k tokens back and forth, and uses so little energy that its single AAA alkaline battery will expire and corrode before fuly discharging.)
A good portion of houses in my country never received a telephone line. Straight from arranging calls between phone booths to mobile.
Before 1989, the state monopoly had an installation backlog of several years (you could only get a line fast if you were high up in the party or had friends at the telco), high monthly fees and was woefully behind on tech: there was no digital voice equipment on the whole network, while the US's Bell trunk network had all-digital audio by 1970. Even until like 1980, in regional towns of 30k-50k, they required you to speak to operators for out-of-town calls. After 1990, the company privatized but it was still prohibitively expensive to get a line set up, as so much money needed to be spent to belatedly bring the network into the digital era. The monopoly ended around 2000 and prices went down but by that point, people saw the dawn of mobile and didn't want to pay for a new phone line anymore.
I forgot to archive my favorite Flash game... I asked the studio behind it and they don't have it anymore :( (There's still the publisher and perhaps people with rare CDs...)
The wavelength has negligible effect on shadow geometry (yes, there is chromatic aberration, refraction, interference but those are very minor in normal lighting, you need special prisms, tiny slits and perhaps lasers to really observe them). What do you even mean?
Also, sunlight (6000K) and daylight (6500K) is pretty much the same color because direct sunlight is >90 % of daylight (the rest is the blue sky and white clouds).
I'm not saying it's a bad idea, I have a red bulb too. It's "handmade" by removing thick red rubber from a "golf ball" decorative 7W CFL and stretching it over a similarly-sized 6W 2700K LED that has instant start and higher light output (not to mention, the taut rubber won't send glass ball shards into a mercury-vapor-filled tube if it happens to fall). It is not as monochromatic as pure red LEDs, I think it's close to what the phosphor-based red ones emit (with a lower efficiency of course since I discard the blue and green while they turn almost all blue into red and no green) and those are marketed as cicardian too. I have to avoid looking straight into it though: the pupil is wide open because rods don't react strongly to red light so long-wavelength (red) cones get massively overloaded and I see a green spot for a while.
The difference is not as pronounced as in the picture. If you're used to 4000K as neutral white, yellowish white is 3000K, amber-ish white is 2700K. Only below the temperature of fire (cca 1500K) is when blue fully disappears and you get actual orange or red. And pure yellow is not a possible black body (incandescence) spectrum (that is, it does not correspond to any color temperature) so even though you can set an RGB bulb to that, buy monochromatic yellow LEDs or go under a low-pressure sodium vapor lamp, such lighting feels unnatural.
Warm white is usually 1800 K to 3000 K. What you showed is less Kelvin than the color temperature of fire (1500 K). We don't have a color temperature word for that, but "red" works. Of course, such light has no blue component (helps control the cicardian cycle) and is pretty much monochromatic with CRI of <5.
"I need a cold light source, like an LED. I'm afraid the fixture would melt if I put incandescent in there." (Yes, some E14 fixtures in cheap plastic bathroom mirrors etc. only take up to 10-20 W and have a warning sticker)
"What, higher temperature is colder?" (It's not their fault though that in nature, white and blue things 🧊 are generally colder than yellow and orange things 🔥)
I sure hope so! I guess fluffy owlets will stay warm easier than when curled up inside a wet egg.