Heinz Mack is a giant of art. Founder of the “Zero” group, opponent of Adenauer, illuminator of the desert. Now, at 91, he wonders what’s left of him.

Mr. Mack, today you are one of the most expensive German painters. Really true that you once had to draw a dachshund in art school to get accepted? Those were sadly the things you had to prove back then. I can’t remember why it was a dachshund in my case. But we had a dachshund at home, so I drew a dachshund, very cute. Then I drew a coffee cup. The cup turned out so well, you could have drunk real coffee out of it. Basically, of course, none of this had any deeper meaning, it was just conventions that were followed. I was interested in other things.