I never got a pass mark in math ... Just imagine - mathematicians now use my prints to illustrate their books.

Are you really sure that a floor can't also be a ceiling?

The things I want to express are so beautiful and pure.

To tell you the truth, I am rather perplexed by the concept of 'art'. What one person considers to be 'art' is often not 'art' to another. 'Beautiful' and 'ugly' are old-fashioned concepts that are seldom applied these days; perhaps justifiably, who knows? Something repulsive, which gives you a moral hangover, and hurts your ears or eyes, may well be art. Only 'kitsch' is not art - we're all agreed about that. Indeed, but what is 'kitsch'? If only I knew!

I try in my prints to testify that we live in a beautiful and orderly world, and not in a formless chaos, as it sometimes seems.

I am always wandering around in enigmas. There are young people who constantly come to tell me: you, too, are making Op Art. I haven't the slightest idea what that is, Op Art. I've been doing this work for thirty years now.

What I give form to in daylight is only one per cent of what I have seen in darkness.