The back

At the Stedelijk there was a section showing how the museum kept their art safe during the Second World War. They built a bunker in the dunes by the sea where they hid priceless art from the Nazis, and implemented a system of marking the back of paintings, according to how important they were. These three paintings were hung back to front to show the different coloured dots (sadly I can't remember which of three colours was deemed "irreplaceable") - don't they look great?! I might blow one of these up big, so I can hang one on our wall...