"The shell designer seeks forms to carry the applied loads in axial compression with minimal bending forces. The earliest example of structural form finding for an arch was published by the English engineer and scientist, Robert Hooke... 1676... As hangs the flexible line, so but inverted will stand the rigid arch. ...'Hooke's law of inversion', can be extended... and considered for shell structures of various geometries. In the context of shell structures, the term funicular means 'tension-only' or 'compression-only' for a given loading, typically considered... Unlike the case of the hanging cable with a single funicular form... hanging membranes have multiple possible forms. ...[T]he three dimensional shell can carry a wide range of different loadings through membrane behaviour without introducing bending. ...[A] three-dimensional model of intersecting chains could be... used to design a design a discrete shell, in which elements are connected at nodes, or the model could be used to help define a continuous surface. If hanging from a circular support, the model-builder could create a network of meridional chains and hoop chains. By adjusting the length of each chain, various tension-only solutions can be found... Once inverted, this geometry would represent a compression-only form. Such... would quickly illustrate that many different shell geometries can function in compression due to self-weight."