Fresh on the heels of the our very popular Hula Hoop Calculus post, we are now bringing you a Hula Hoop Geometry lesson. The Museum of Mathematics have featured a wide array of different items from which one can make a tremendous variety of geometric constructions, but there has not yet been one on hula hoops – until now. Why hula hoops? Glen Whitney explains, “They’re a pretty cheap source of large, pre-made circles, generally decently symmetric and strong. So they’re a candidate for any large-scale building project that can be based on the geometry of a circle. What are some examples? Well, you can envision each circle as a great circle on a sphere, and ask: is there a way to arrange four of these so that every intersection point between great circles is equidistant from its nearest neighbors?” Apparently so. The feature shows some definitive examples and constructions for those with a love of mathematics and hooping to check out.