alt.hn

2/19/2026 at 4:27:23 AM

ReferenceFinder: Find coordinates on a piece of paper with only folds

 https://mutsuntsai.github.io/reference-finder/

by icwtyjj

2/22/2026 at 1:36:28 PM

That is really cool. I wish it had an animated video to display the result, that'd be even easier to follow and therefore even more impressive.

by Ecco

2/22/2026 at 4:08:47 PM

Maybe possible with that DSL the YouTube channel 3Blue1Brown created?

by Alifatisk

2/23/2026 at 5:04:53 AM

Manim

by vismit2000

2/22/2026 at 3:00:48 PM

I enjoy when HN surfaces out-of-the-box type stuff like this. Very cool.

by JKCalhoun

2/22/2026 at 6:23:57 PM

“outside of the box”?

by scoot

2/22/2026 at 2:08:59 PM

Is this brute forcing, or is there more to it?

by amelius

2/22/2026 at 2:55:07 PM

There's more to it. Origami as a calculation tool is more powerful than compass and straight edge.

by PowerElectronix

2/22/2026 at 8:45:11 PM

Is there? I followed the link[1] to the original author of the desktop software this web app is derived from, and he says:

> To make a long story short, by the third generation of ReferenceFinder (written in 2003), I had incorporated all 7 of the Huzita-Justin Axioms of folding into the program, allowing it to potentially explore all possible folding sequences consisting of sequential alignments that each form a single crease in a square of paper. Of course, the family tree of such sequences grows explosively (or to be precise, exponentially); but the concomitant growth in the availability of computing horsepower has made it possible to explore a reasonable subset of that exponential family tree, and in effect, by pure brute force, find a close approximation to any arbitrary point or line within a unit square using a very small number of folds.

(emphasis added)

[1] https://langorigami.com/article/referencefinder/

by CrazyStat

2/23/2026 at 4:38:54 PM

There's brute force involved, but it's not brute force by itself. It's like a chess engine, which yes, it checks thousands of positions, but only after filtering out hundreds of thousands of positions.

by PowerElectronix

2/23/2026 at 7:06:33 PM

Are you involved in writing or maintaining this software? If so can you provide some more details on this “filtering”? Because I skimmed the source code [1] and it looks to me like it’s pure brute force building a database of lines and points up to a certain rank (number of operations required to create that line/point) and then searching through it.

[1] https://github.com/MuTsunTsai/reference-finder-cpp/blob/main...

by CrazyStat

2/23/2026 at 11:35:15 PM

No, you are right. The author even uses the expression "by pure brute force". I just supposed it would given that virrually every number a user would input is constructible with foldings.

by PowerElectronix

2/22/2026 at 9:04:06 PM

Folding could be called a superset of measuring.

Measuring could be called a special case of folding (it's an accordian fold)

by analog8374