Oh, here's a photo of mine.
The foam is attached to 20"x40" masonite panels that are held to the wall with 2 standard wall anchors, so removal would only take a minute per panel with minimal patching - a hint for renters.
After I found that double-sticky carpet tape would only hold the foam for a few days, I used Arlene's Foamtastic glue (just a few sqiggle lines over each foam square area is neccesary; you don't have to cover the entire panel with glue.) No square has moved since I used the Arlenes.