I once walked up to my house and the automatic lights turned on while I was straining to see the door. It was a halogen light which is petty standard for these type outdoor lights, and it probably was a spot-light type. It physically hurt and I had a spot in my vision for months. There were several things that resulted in this accident: 1) spot light 2) pupils at max opening 3) light skin genetics that make eyes less durable to strong light (my wife from peru never squints in bright sun, while I always am squinting (maybe it's due to lighter-colored irises)) 4) cold weather means cold filament which means higher current which might have meant higher-intensity light. Filament-type lights burn out from turning on too often from this excess current. 5) there's not enough intelligence in the marketplace to prevent this type of accident. 6) there's not enough intelligence in democratically-elected governments to prevent this type of accident. 7) there's not enough intelligence in humanity as a whole to improve 5) and 6). 8) there's not been enough time and enough depletion of resources enough to prevent births or cause more deaths to increase human intelligence and morality (working together for the greater good). 9) machines have not yet had enough time to replace biology.
While feeding my infant a few years ago, I realized the shaking of the head to indicate "no" apparently comes from babies turning their head from side to side (with a sour face) to reject food parents try to force on them. In the brain, food and information have strong parallels, as language often indicates. So rejection a proposition is like rejecting food. Before she could talk my daughter used shaking of her head to say "no" to things other than food. Nodding up and down does not get the mouth as far away from food, and even turning the head up may allow food to enter more easily especially if fed from "above". "Ahhh, I see" will start with the head going up to accept a proposition of "higher" authority or trueness than previous a previous position.
I've thought of a way to measure light intensity in W/m^2 using the heat capacity of a black-painted piece of metal, an infrared thermometer, and measuring seconds.
It's strange to me that sometimes there are problems that are discrete or involve integers and I have no way to solve them or work with them mathematically except by trial and error, or some un-expressable reasoning. Examples: rubics cube. Example: 3 equations and 3 unknowns that use only integers. Example: Given a balance and 12 balls that look the same except one weighs less or more, how do you weigh them in 3 tries to determine which one weighs differently? How do you set this up mathematically to try to calculate (that is, logically proceed) towards an optimal solution (fewest weighings) without having to resort to trial and error?
I have read and seem to have experienced that puzzles are easier to solve the older I am, as long as short term memory is not required (the lack of which might be the cause of many mistakes). Maybe practice on logic puzzles (as opposed to "math") especially if they are cast in terms of competition and profit should be a 6th leg of education (the other 5 being language, math, nutrition, social, and exercise).
Aluminized mylar on foam boards supported on the sides and bottom of windows could be used to reflect 2.5 times more light into the house than the window itself during peak hours. If they were then closed at night for insulation, half the U.S. could have 30% less heating cost, paying for itself in 2 years.