No. 524 - arriving mail art "Otto Zirkus" from Heinz W. Lotz (Germany)

No. 524 - arriving mail art "Otto Zirkus" from Heinz W. Lotz (Germany) - another postal experiment from Heinz without any valid postage stamp, he collaged the backside of this official card completely with some illustration of a circus, in which Bismarck seemed to be an artist. Thank you very much.