Meccano differential analyser by Douglas Hartree

This is a reconstructed machine for solving complex mathematical equations, originally made in 1934 by mathematician Douglas Hartree and his student Arthur Porter from the construction toy Meccano.

It was one of the first electromechanical computers. It used the movement of shafts and gears as the physical analogue of the mathematical relationships. Later digital computers electronically manipulated the numerical values themselves.