To translate the final answer from math to human (as I’m going to be explaining this to my mother when I chat with her next!):

Imagine the half onion is a half rainbow. You know there’s another half rainbow lurking below the surface, the onion’s ghost of the sphere it once was. Place your knife as usual for each of your ten dice cuts, but instead of cutting straight down towards the cutting board, angle it slightly inward towards the end of the onion’s ghostly half-rainbow sphere below the board. Check your fingers for safety and then make your cut. Assuming your knife isn’t a plasma cutter, you’ll be stopped at the cutting board without ever reaching the onion at the end of the rainbow, and that’s cool. Set your knife at the next dice point and try again :)

(This still improves on the other dicing cases and only costs 1% uniformity by using 100% radius as the target.)

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fnord77 4 days ago | parent [-]

> Place your knife as usual for each of your ten dice cuts,

what does this mean, exactly? I don't cut onions. Also I assume there is some pre-step where you cut the onion in half on some axis, but I don't know which.

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altairprime 4 days ago | parent | next [-]

If you inspect the onion diagrams in the article carefully, they show various ways to cut an onion, as if origami diagrams but with knives. Still, I think you’ll want to learn the traditional methods of dicing an onion independently first, and then with that knowledge revisit this article and my description; this is last-10% optimization work that hinges on knowing that first-90% of how to dice an onion at all.

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zeroonetwothree 4 days ago | parent | prev [-]

If you don’t cut onions you probably shouldn’t bother with this thread. Or at least watch a video

	▲	fnord77 4 days ago \| parent [-]
		gate keeping onion cutting? really?