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Comment by jonnycomputer | Hacker News Reader

I think I'm missing something. The algorithm shuffles to prevent words in adjacent squares from being the same? Why not just draw from the set of 3-permutations and if satisfies that adjacency constraint, remove from the pool of available permutations (conditional draw without replacement). A solution would only have to be found once anyway, right?

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Their business model is to own access to the dataset. They don't want hierarchy as they want people to be required to use their software every time they interact with these addresses. They're just scummy. There's no reason to use this scheme vs a hierarchical decomposition using something like S2.

Storing a full lookup database on every device is not pratical.

With ~3 million squares it would fit in a couple hundred megabytes at the very most, even without any compression. It may not be optimal, but it's certainly not unrealistic either.

The squares are 9m^2, surface area of the earth is 510 trillion m^2, so there’s about 50 trillion squares. You’re not fitting that in an app

I think the surface area of the earth is 196,936,994 m^2 That's 21,881,888 3x3 squares. The surface area of Jupiter is 23 trillion m^2.

It is 510.1 trillion m² (google result).

3x3 is 510.1/9 - 56 trillion (and change).

> 196,936,994 m^2

Is equivalent to a perfect square with sides 14km long...they say it's a small world..but not that small.

The explanation of the discrepancy is that I had interpreted the numbers in OP article and in parent as miles, not meters.

https://solarsystem.nasa.gov/planets/earth/by-the-numbers/ Volume: 6.73 x 1011 cubic miles (1.083 x 1012 km3) Radius: 3,959 miles (6,371 km) Diameter: 7,918 miles (12,742 km) Surface Area: 1.97 x108 square miles (5.1 x 108 km2) Mass: 5.972 x 1024 kg

The standard symbol for "square miles" is "sq mi."

"m²" or "m ^ 2" universally refers to square meters (unless you've established unambiguously that you're talking about miles — and even if you have it should still be "sq mi").

Your surface area is totally incorrect.

It is not incorrect. Its in US miles, not meters. I mistook the original as posting in miles and responded in kind. meters makes more sense--more fine-grained.

Yes, that's pretty much the definition of incorrect.

Again, I think I'm missing something. Apps don't maintain a complete local database or resource records for the domain name system either. We access name-servers for that information. So I think I'm missing the use case for this system.

A design requirement of the app is it works offline.

Ok. That makes sense.

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