As an artist, Piet Trantel made a lot of money. Nonetheless, he wasn't happy. 'I didn't want to sell my art,' Trantel says. 'I kept repeating sculptures that sold, and I started to question what I was doing. I wasn't satisfied.' The German's change of heart also resulted in a change of direction - to conceptual art. 'No one buys it, but I'm happy and have no regrets,' says Trantel, who supports himself doing such odd jobs as working in an apple-juice factory, painting advertising hoardings and teaching art. The third of four children in a farming family, Trantel learnt to paint as a teenager. After school, he became a policeman, but began to realise he preferred painting to patrolling. So, he quit the force and held his first exhibition. He then enrolled in the Fine Arts Academy in Braunschweig, majoring in sculpture. After he graduated in 1986, he won first prize in a German Ministry of Education and Science arts competition with a steel sculpture, and his career was launched. But he came to realise happiness didn't lie in money. His conceptual art is expressed through sculptures, film, poems and human behaviour. He is especially interested in making conceptual art in public spaces, but questions his right to invade people's lives. In an effort to prompt people to think about artists' rights to use public space to display their works, he once put a dirty weed-filled ditch in the middle of a beautiful garden in a Hamburg park. 'His conceptual artworks include an exhibition about his one-month solo walk from northern Germany to the Black Forest in the country's south. The show consisted of a chair, a table and a telephone with which visitors could call him while he was on the road. 'I used my mobile telephone and words to paint the landscape I saw,' he says. Another example of his work was his move in 1996 to declare the 'International Day of Non-Doing', to encourage people to reflect on their busy lives. In 1999, wanting to let people know that there are many more things in life than arts, he moved on to set up his own social project, Life Service. With the help of friends and a hotline from his Hamburg home, he offers non-monetary assistance to anyone in need, including climbing to a second-floor flat to open the door for an elderly woman and counselling people. 'A man called and said he wanted a new motorcycle,' Trantel says. 'Later, he said he also wanted a girlfriend. And in the end, he said he wanted a new life. I could help him find a girlfriend, but I couldn't give him a new life. At least we opened up the communication and a chance for him to think of his life.' After setting up the group, Trantel stopped doing arts. Since April, he's been teaching creativity at Zhuhai's Beijing Normal University. Life Service in Hong Kong is his first comeback in art, but he regards it as part of his Life Service works. He says he'll continue do society art work.