On top of the points others in this thread have made, I think this is also a lesson for UX designers. It's really obvious how the Yayagram works and how to use it and this is how our UX should be.
It’s effective because it’s as simple as possible, and relies heavily (as pointed out by the designer multiple times) on very old metaphors like switchboards, telegrams, and binary state indicator lights. It feels obvious because these metaphors have been in our lives for decades, so we’re very familiar with them. But it doesn’t mean that we didn’t have to learn them at one point. It’s sort of like how the Beatles sound like regular music today, but in their heyday they made very new sounds and lots of people thought it was shit music.
I feel like UX designers are devalued because they often seem to create irritation rather than harmony. Let me tell you, it’s a real pain in the ass making harmonious experiences when you’re playing second fiddle to short term business goals, or even third fiddle to short term engineering constraints. I would love to go into Gmail and declare it a finished product and get the whole team to spend a year figuring out which features we can strip out to simplify the product and design it holistically like this Yayagram, but it’s a terrible business decision so we’re not doing it.
In real life, UX designers are there simply to prevent large apps from devolving into CRUD hell, and it’s nearly Sisyphean.
Thinking this way becomes incredibly important as systems move from dedicated devices further into coordinated actions of ubiquitous devices.
Even if you found someone who's confused by the use of wire in this device, I think a 30 second explanation and demonstration would clear it up forever.
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[0] - Excepting the Sentinelese, and some other remaining groups with zero exposure to industrial-era technology - of which there's very few remaining on the planet.
[1] - And even in case of people who have never seen electrical devices, you can easily come up with a simple analogies to transfer this concept across all advancement levels. Voice traveling along a taut wire. Water flowing down the gutter. Grain rolling down a chute. Water dripping through, or flowing along, a soaked string. A bolas. Poking a bear with a stick. Etc.