Post-Modernism

I like idea the postmodernism is revolutionary and combines a little bit of everything.  This is very appealing because you can always find something new and something that relates to you.  That being said, it is also hard to grasp.  For example, the author described it as having "a new kind of flatness or depthlessness".  If a painting is 2D I find this very hard to understand.  Does the author mean the picture is not as 3D or there is not as much meaning?  This mystery also is appealing because there is never one correct answer.  Postmodernism is confusing, but very interesting.