Frustrating frustration in snap-induced morphing

The bistability of embedded elements provides a natural route through which to introduce reprogrammability to elastic meta-materials. However, attempts to leverage this programmability in objects that can change shape, or morph, have been limited by the tendency for the deformations induced by multiple elastic elements to be incompatible --- deformation is frustrated by geometry. We study the root cause of this frustration in a particular system, the soft morphable sheet, which is caused by an azimuthal buckling instability of bistable elements embedded within a sheet. With this understanding we show that, for this system at least, the root of frustration can itself be frustrated by an appropriate design of the lattice on which bistable elements are placed.