The Rodscule. The inner and outer rod, Σ′,Σ, (red) are defined by an inner and an outer ellipse, Γ′,Γ, (blue). The 3 points P,Q,R (yellow) define the ellipse and, hence, the Rodscule. M is the barycenter, K1 and K2 the centers of the semi-circles of the inner rod, C 1,C 2 the centers of the semi-circles of the outer rod. e4 and e4 are the extremal points of the inner and outer ellipse respectively. They define the common points of each ellipse with its corresponding rod, where it is inscribed.