Hungarian-born abstract artist Viktor Vasarely has opened a Budapest museum housing more than 500 works given by him to the country he left 57 years ago. The Vasarely museum, set up in a wing of Budapest's 18th-Century Zichy palace, traces the artist's stylistic development through to the rippling geometric patterns and optical illusions that are his trademark. "I'm asked if I'm a great patriot," the frail 79-year-old Vasarely responded to a question at a news conference on why he had donated the multimillion-dollar collection to Hungary. "I'm a citizen of the world," he said. He now lives in Aix-en-Provence in France.