"Before the invention of the GDP, economists were rarely quoted by the press, but in the years after World War II they became a fixture in the papers. They had mastered a trick no one else could do: managing reality and predicting the future. Increasingly, the economy was regarded as a machine with levers that politicians could pull to promote "growth." In 1949, the inventor and economist Bill Phillips even constructed a real machine from plastic containers and pipes to represent the economy, with water pumping around to represent federal revenue flows. As one historian explains, "The first thing you do in 1950s and '60s if you're a new nation is you open a national airline, you create a national army, and you start measuring GDP."