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Comment by InsideOutSanta | Hacker News Reader

Yeah, I at first, I though I knew exactly how it worked. Then I saw the search field, and I suddenly had no idea what the hell was going on. Now, the big question, do I want to spoil the magic trick and read how this was done, or should I keep being astonished and flabbergasted?

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I disagree with my sibling comment. The trick is beautiful. If you generate UUIDs such that each bit in the result can be reliably traced back to a single bit in the input, then you can take a substring of the UUID and use that to infer which bits of the input integer must be set to produce that substring. So you can produce a whole list of input bytes that meet the criteria and those become your search results.

The real magic trick here is that the uuids on the page only look random to us because of some bit twiddling and XOR trickery. If we had a better intuition for such things we would notice that successive UUIDs are just as correlated as successive integers.

Elegant stuff

> I disagree with my sibling comment. The trick is beautiful. If you generate UUIDs such that each bit in the result can be reliably traced back to a single bit in the input, then you can take a substring of the UUID and use that to infer which bits of the input integer must be set to produce that substring.

...but that has nothing to do with what the website is doing. The accompanying article specifically calls out the fact that it can't be done while maintaining the appearance of an unordered list, and therefore it isn't attempted.

If you're an Everettian, roll https://www.jrussellhuffman.com/quantumdice/ and read it only if the die is odd. You can have your cake and eat it too.

Genius.

As with any magic trick, reading the explanation might leave you a little disappointed here.

I'm the opposite. The magic is not in what the magician shows, but in what they elegantly manage to hide.

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