"The formal models of Gödel (1931-34), Church (1935), Turing (1936), and Post (1936) were theoretical pen & paper constructs that cannot directly serve as a foundation for practical computers. Remarkably, Konrad Zuse's patent application[ZU36-38][Z36][RO98] for the first practical general-purpose program-controlled computer also dates back to 1936. It describes general digital circuits (and predates Claude Shannon's 1937 thesis on digital circuit design[SHA37]). Then, in 1941, Zuse completed Z3, the world's first practical, working, programmable computer (based on the 1936 application). Ignoring the inevitable storage limitations of any physical computer, the physical hardware of Z3 was indeed universal in the "modern" sense of Gödel, Church, Turing, and Post—simple arithmetic tricks can compensate for Z3's lack of an explicit conditional jump instruction.[RO98]"