The station was soon flooded with letters from radio listeners asking where they were supposed to look to see the concert. The Berlin Olympics were transmitted by television, and in March 1936 a video telephone system was established. While England, the USSR and the USA lowered or outright ceased transmissions during World War Two, Germany paused only during the invasion of Poland. If the BBC had not adopted the EMI system, it is unlikely England would have had the facilities to manufacture cathode ray tubes on an industrial level. Mechanical imaging systems remain a vital technology.
Computer mice use two slotted disks that are rotated by the track ball.
Software or sound activated moving mirrors are the key component to laser light shows as well as some virtual reality headgear. All of these technologies, as well as television, are directly indebted to John Logie Baird.