Tetraform nanoprecision machine tool. This machine, developed at the UK's National Physical Laboratory, was intended to be used to carry out machining (shaping devices and components) to nanometre accuracy. The tetrahedral geometry provides inherent stiffness and symmetry. It also avoids excessive vibrations by having a resonant frequency greater than 1 kiloHertz. This machine, the Tetraform 1, was developed by Kevin Lindsey in 1992. Photographed at the NPL, Teddington, UK.