Reading up a bit about Kurt Schwitters and checking out his work. "Whereas the raw material of most of the Dada montage of the times was photographic and relevant, Schwitters took his from the streets. The montages, collages and assemblages that he constructed from all this gathered refuse have an extraordinary integrity of vision, but they are certainly not in any way political,..." found here at cut and paste. His Merz was really something. I wish I could have seen the merzbau.