For some people, art is an act of extreme patience. Certain master's works can take months and even years to finish. There are some other artists who seem to found ways to streamline the entire process down from Weeks to days, from days to hours, and finally, from hours to minutes.
Take, for example, this street artist in Rome. While it may look like he is starting with a simple rainbow, what he ends up with with will amaze you.
Just speaking from experience, if I were to try and duplicate that, it would take me sixty-three months. Just trying to put it in perspective just how impressive this guy is.