Signed postcard of the German Fluxus, happening, and performance artist's print "Grassello - CA (OH)2 + H2O" which accompanied his April 1979 performance piece of the same name. He has signed across the image and inscribed at the foot in German. Stamped on the verso by the German environmentalist party Die Grünen. Very fine. 4 x 6 inches (10.5 x 15 cm).