Apparently casual, these announcements or invitation cards can be a vivid and atmospheric way into different artistic positions. Often conceived of quickly, printed in a rush and dispatched to friends and colleagues, the words and images on simple cards or even a personal note, can carry deliberate artistic significance. Richard Hamilton printed "Don't Forget" followed by Marcel Duchamp’s signature as a nod to Duchamp's delight in the force of fleeting messages. Other printed matter by Marcel Broodthaers, Hanne Darboven, Jeremy Deller, Marcel Duchamp, Yves Klein and others.