Now, think about where the world would be today if we had the light bulb, but you couldn't focus light; if when you turned one on it just went wherever it wanted to.
Acum, gândiți-vă unde-ar fi lumea de azi dacă am fi avut becul dar n-am fi putut focaliza lumina; dacă atunci când ai fi aprins unul, lumina ar fi ajuns oriunde ar fi vrut.