On designing a tetrahedron-like shape that is only stable on one face.

"[I]n a preprint posted online yesterday, they have presented the first working physical model of the shape. [...] To work, it had to be engineered to a level of precision within one-tenth of a gram and one-tenth of a millimeter. But the final construction always flip-flops onto one face, exactly as it should."

https://www.quantamagazine.org/a-new-pyramid-like-shape-always-lands-the-same-side-up-20250625/

#Tetrahedrons #Geometry #MonoStable #Structures #Mathematics

Today, I learned that some football clubs are using Reuleaux tetrahedrons instead of spherical balls in training to improve goalkeepers' reflexes. https://en.wikipedia.org/wiki/Reuleaux_tetrahedron

Video source: https://x.com/futebol_info/status/1899217444235043025

#Football #FootballClub #FootballClubs #Club #Clubs #Spherical #Reuleaux #Tetrahedrons #Tetrahedron #Ball #Balls #Geometry #Sport #Sports #Soccer #Goalkeeper #Reflex #Reflexes #Training #InterestingPost #Pustam #Raut #Math #Maths #CR7 #LM10 #LeoMessi #LionelMessi #CristianoRonaldo #Ronaldo #FootballTraining #ReflexBall #Messi