"What I'm doing is negative work," he said. "You have to do something by undoing it. Everything is disappearing once more. You have to dare to give the final brush stroke which makes everything disappear."

"That's a daring you don't lack," I remarked.

"It's not as easy as you may think," he answered. "Sometimes it's very tempting to be satisfied with what's easy, particularly if people tell you it's good."