Right-angled equilateral heptagon can form a 1 degree of freedom linkage in two distinct ways Posted on 2021/10/15 by Carl Robitaille I was surprised to learn that a right-angled equilateral heptagon can form a 1 degree of freedom linkage in two distinct ways. https://t.co/6uiK2YwkA0 pic.twitter.com/MRTFk60vbc— Daniel Piker (@KangarooPhysics) October 8, 2021