The researchers’ first step was to characterize this diversity with two measurements. First, ellipticity: start with a sphere, and as you stretch it out, it becomes more elliptical. Second, asymmetry: sometimes, one end of an egg is pointier than the other. Each of these measurements is a continuum—values can fall anywhere in the middle—and by combining them, you can describe nearly any egg. Asymmetrical and elliptical? Like a teardrop. Symmetrical and spherical? That's a sphere, duh.