Jay DeFeo's incredible painting, The Rose is one of my favorites. It's a painting and a sculpture. The paint is so thick, she carved and cut into it. It went through many changes and evolved from a flat plane to the sculptural landscape it is now.
She spent 8 years working on it; allowing it to go through its own evolution. Apparently, she had a T.V and a radio on while she was painting in order to ingest information so she could translate it into the painting. I love that idea of having to input in order to output.