  Gaussian-curved shapes are obtained by inflating initially flat systems made
of two superimposed strong and light thermoplastic impregnated fabric sheets
heat-sealed together along a specific network of lines. The resulting inflated
structures are light and very strong because they (largely) resist deformation
by the intercession of stretch. Programmed patterns of channels vary either
discretely through boundaries, or continuously. The former give rise to
facetted structures that are in effect non-isometric origami and which cannot
unfold as in conventional folded structures, since they present localized angle
deficit or surplus. Continuous variation of channel direction in the form of
spirals is examined, giving rise to curved shells. We solve the inverse problem
consisting in finding a network of seam lines leading to a target axisymmetric
shape on inflation. They too have strength from the metric changes that have
been pneumatically driven, resistance to change being met with stretch and
hence high forces like typical shells .
