No. 30 - arriving mail art "der Bismarckhering - der Pottwal" from Anonymous (Germany)

No. 30 - arriving mail art "der Bismarckhering - der Pottwal" from Anonymous (Germany) - a postcard from Daniel Behrendt "Postkarten an Mutti" has been used for this additional collage over it. Maybe it has been done from Heinz W. Lotz, but there is no sign on it. Thank you very much