»Billboard 01«, 1991 by Gerwald Rockenschaub. Rockenschaub based his work on the modular system used by the poster company gewista, whereby each large-format poster is made up of 8–72 standard format sheets. He had these sheets printed in monochrome in seven industrial norm colours from which he made forty colourful combinations which could be independently selected on the spot by whoever was putting up the poster.