He is said to have claimed that it took him fifteen years to learn to paint like a man and the rest of his life to learn to paint as a child. And, certainly, there is a childlike quality to Picasso's work. There is a playfulness and an obnoxious disregard for "rules" that we find both delightful an yet disturbing. Even though he's now been dead for 25 years and his life's work stands as a whole, we still have the uneasy feeling we're not sure what he might do next. Yet, despite his seeking after childishness, there was never a man who explored art more seriously.
Picasso's exploration of art surprisingly straight-forward. He learned all the rules, then he systematically explored all the ways to break them. He learned to create the illusion of volume then he deliberately learned how to flatten it. If you study his work, you can trace very nearly a step-by-step progression from realism through Cubism, stopping just short of non-representational abstract expressionism. When people think of Picasso, abstraction comes to mind, but with abstraction comes a LACK of rules, and Picasso loved rules, because without the "rules" of art, he had nothing to bend or break.