If you are of a certain vintage, this image is burned indelibly somewhere in your posterior parietal complex: Oh, my old friend. How it’s been a long time. Cultural Significance For the uninitiated, what are we looking at? Could it be the Moiré Error from Doom? Well, no. You are looking at (part of) the boot up screen for the X Window System, specifically the pattern it uses as the background of the root window.