Design company Cellule GmbH has created a unique piece of functional art called the Pebro Bench. The Pebro Bench is a form of public seating that becomes a sculpture when unoccupied.

When no one is sitting on it, the Pebro Bench rises on its own, from one side, to become what The Design Blog calls “an elegant structure." It's perfect for parks and other public places. The user just has to pull the Pebro Bench back down in order to sit on it.