Since the Bronze Age, humans have put to use the inherent compliance of liquids to shape matter and construct objects. Metal casting, glass blowing, painting are all examples of processes where a final construct is obtained following the solidification of an initially liquid phase. Throughout history, this concept has matured into a plethora of industrial processes, e.g. in the polymer industry. Those engineering successes, however, come at the expense of simplicity. Specifically, processes are generally largely tuned empirically with compromises between versatility and reproducibility. I propose to explore new paradigms in the design, the engineering, and the manufacturing of structured and functional materials, using free surface gravity driven flows, and harnessing their fluidic instabilities. Three examples will be presented: (1) a fluid-instability based approach for digitally fabricating geometrically complex uniformly sized structures in molten glass, (2) the rapid fabrication of nearly uniform hemispherical elastic shells by drainage and (3) their pneumatic  actuation towards shape morphing applications.