"Liquid" structures consist of elements linked up via punctiform or linear joints. These structures are flexible or can be folded up and it is possible to turn them into a rigid structure through fixation or addition of elements. A comparison with physical phenomena is allowed here, i.e. with the states of matter: the loose elements can be compared with the gaseous state, the movable joint structure with the liquid state, and the introduction of further parts producing a rigidity of structure is analogous to crystalisation.
SPHERICAL STRUCTURE FOLDED AND UNFOLDED