 This required the performance of many routine calculations by hand, which he found mind-numbing, leading him to dream of doing them by machine.Beginning in 1935 he experimented in the construction of computers in his parents' flat on Wrangelstraße 38, moving with them into their new flat on Methfesselstraße 10, the street leading up the Kreuzberg, Berlin.Working in his parents' apartment in 1936, he produced his first attempt, the Z1, a floating point binary mechanical calculator with limited programmability, reading instructions from a perforated 35 mm film.