Egg painter
Four hundred years ago, there's an Italian guy named Leonardo da Vinci. He's a famous painter. When Leonardo da Vinci started learn to paint, his teacher first ask him to paint an egg, he painted it one by one. He started to get nerves and impatient, so he ask"My teacher, you're asking me paint eggs everyday, isn't it too easy?" The teacher said to him seriously"You thought it is easy to paint an egg, but you're wrong. Among those egg in a thousand, none of it are totally in a same shape. Every egg would be looking different while you're using different angle. The reason why I asked you to paint an egg, is to train your abilities of sight focus and painting technique. So it makes you're view accurate and paint it with skills." Leonardo da Vinci listens to his teacher, paint it one by one, every piece of paper fill with different shapes of eggs.
Since then, whatever Leonardo da Vinci tries to paint, he always paint it fast, and alike.
I translate this by myself, hope this help :)