Fig. 5.

The same point set X with balls of radius r, and the threefold cover highlighted in darker pink. In black, the degree-3 Voronoi tessellation, which is the superposition of the order-2 and order-3 Voronoi tessellations. It decomposes the threefold cover into convex pieces. In blue, the dual of this decomposition, $D_{2.5}:={\mathrm{Del}}_{2.5}^{}(X,r)$. The additional green cells are part of $E_{2.5}\supseteq D_{2.5}$