  Inverse design aims at the development of elementary building blocks that
organize spontaneously into target shapes. In self-assembly, the blocks diffuse
to their target position. Alternatively, recent experiments point to a more
robust process in which the shape is formed from the self-folding of a planar
template. To control the folding of templates with competing folded structures,
we propose the inclusion of bond specificity. We consider a template that can
fold into an octahedron or a boat shell and find the minimal design capable of
targeting either shell or switching between the two through an external
stimulus, adding a new dimension to the design of shape-changing materials.
