There existed watches with the same digits, features and buttons before that, but they were in steel. 1989 is about when Casio transitioned from metal to resin.
The metal watches were succeeded by the A158W, which is chrome-plated resin on the outside, same electronics module as the F-91W on the inside, and likewise is still in production.
After the resin case of my A158W eventually broke, I got a vintage W-34 with a broken movement and put the A158W's module inside. (It will get a SensorWatch PCB once I am done with my firmware mods)
Steel replacement cases for a F-91W are now also available on Aliexpress, so you don't have to hunt down a vintage watch if you want real steel.
The F-91W is such a fun watch. Super functional, you're not scared of damaging it, because A) You can't and B) it's like $25.
The backlight is my absolute favorit feature. It's completely pointless. It can barely light up the hours, and only the left most digit and Casio never bothered to fix it. Absolutely delightful.
Casio is still super hit or miss with backlights. I have a Casio Lineage LCW-M100TSE-1AER and the light is even less useful for its display. Otherwise it's very nearly a perfect watch for me.
I always bump the 24H button on the F-91W, I'm not entirely sure why Casio felt like you should be able to switch between 12h and 24h at the push of a button. My assumption is that most people stick to either of the two formats, jumping between them seems like a edge case.
But, the obvious failure mode: you assume it locked automatically behind you, but how can you be guaranteed of this without checking? It seems to me at that point it's better to just lock it with a key, which guarantees it's locked.
I get a notification when the doors lock. I can also check the status of the lock in Home Assistant.
If for some reason the deadbolt jams, or the door was not actually locked, then I risk it for those few hours. It hasn't happened yet.
I have probably "manually" forgotten to lock my door more times than that. (e.g. Carrying items out to the car, I think I will go back for more, then I get distracted and leave instead.)
I like my auto lock feature, but I manually lock it as a habit and only rely on the auto lock as a backup in case I forget. I only have to touch the keypad to lock it and can hear it lock. Also, I can check remotely if it is locked (even though the lock can/does work completely without a need for a connection).
I need a geologist to explain this one. Moissanite has a Mohs hardness of 9.5. I guess it is easier to scratch than a diamond, but the scratability should be indistinguishable between the two for all practical purposes.
Not a geologist but Mohs hardness is an ordinal scale so the distance between 10 and 9 isn't well-defined. The numbers are defined as being specific minerals.
Diamond (10) is 4x as hard as corundum (9) which is 2x as hard as topaz (8).
While (human) vision is 3 colors, reviews of visual arts obviously can't just describe the colors of the thing. It also has shape, depth, style, etc.
Food reviewers don't note the levels of salt, sour, etc. They describe flavors and textures and parings.
But also, I don't buy that taste is just the composition of 5 components. This sounds like a reference to that diagram of the tongue we've all seen. It's as complex as scent is. There's no way you can define the taste of cinnamon by specifying some sort of 5-tuple.
I believe he is correct. The misunderstanding is from the old chart that showed certain tastes were only detected by certain parts of the tongue.
It’s still true that we can only taste salty, sweet, sour, bitter, and umami. All other flavor complexities come from scent simultaneously giving us information. It’s why everything tastes so boring when you have a head cold.
Think about this, suppose you're on a Zoom call and you want a person on the other side of the call to match a color that you're seeing. You can say "make it more blue", "make it brighter", "shinier", etc.
You can get pretty close to what you're seeing this way.
This isn't a food storage thing, but I think I see where you got that idea from the photos in the link. He's showing the types of paperboard that work with his system. Old cereal boxes, coffee filter boxes, etc.
I wasn't too surprised to see their blurb leave out it's other (alleged!) known use
https://en.wikipedia.org/wiki/Casio_F-91W#Usage_in_terrorism