alt Hacker Newsthe title is a classic quant interview problem
the basic idea is that, because multiplication commutes, probability of A then B is the same as probability of B then A, so long as they are independent events (rolling objects typically meets this criteria)
so instead of using just A or just B, which might neither have 0.5 probability, you only count "A then B" and "B then A" as rolls
and this trivially extends to constructing a fair N-sided die out of any arbitrarily biased die for any N
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ethan_smith • today at 3:02 AM
This technique is formally known as the Von Neumann extractor (1951), a foundational concept in randomness extraction.
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That isn't what the article is about at all. It's not even what the first paragraph is about.
What they are doing is designing physical shapes that will have a specified probability of falling in different positions.
What you are talking about is post processing a biased random signal to get a less biased signal.