Post #1743290
2026-04-25 20:43 UTC
Aerodynamically stable umbrella
Replies (1)
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@tpfto@mathstodon.xyz 2026-04-25 21:52
@markusde@mathstodon.xyz Admittedly, I didn't try looking very hard, but: https://patents.google.com/patent/US20050247334 There might be others...