This chapter provides a description of the technology of Unicorn focusing on simple, efficient and general algorithms and software for the Unified Continuum (UC) concept and the adaptive General Galerkin (G2) discretization as a unified approach to continuum mechanics. We describe how Unicorn fits into the FEniCS framework, how it interfaces to other FEniCS components, what interfaces and functionality Unicorn provides itself and how the implementation is designed. We also present some examples in fluid–structure interaction and adaptivity computed with Unicorn.