The Forgotten Flexagon - Numberphile
Why the open web links it
Explores the mathematical curiosity of flexagons, their history, and how they work.
Linked by 5 independent sites, 2 of them widely read in the 2026-10 crawl of the open web, including nsw.gov.au, mee.nu, make.co, petemcpartlan.co.uk, puzzlebyrinth.com.