Fig. 4From: Mechanics of moving defects in growing sheets: 3-d, small deformation theoryA W2,2 hyperbolic surfaces in \(\mathbb {R}^{3}\) that is built by patching together (smooth) quadratic maps on the 6 sectors shown in (a). The straight lines in the surface (b) are the images of the straight lines in the unit disk (a). The existence of such straight lines is a consequence of hyperboloids being doubly ruled surfacesBack to article page