Topological interlocking as a material design concept

We review the concept of topological interlocking of identical elements in single-layer structures on which we have been working over the last decade and outline its advantages over monolithic structures. Multi-layers involving topological interlocking are also introduced and their unusual properties are discussed. In a broader sense interlocking also occurs in living organisms, and a connection of our artificial, geometry-inspired design to some recent observations of interlocking in nature is made.