Viennabike and Shopping cart
These bikes were offered by the municipality for free. You could unchain the bikes from public terminals by inserting a two euro coin in the lock. It is the same system like for shopping carts. When you returned the bike you had to chain it at another terminal to get the coin back. After some time almost all bikes were gone, so the city stopped the project and sold the remaining bikes. When you bought a bike you recieved a certificate proving you didn´t steal it. The artist bought one and combined it with a found shopping cart.