Grassroll was a long, air-inflated rubber tube covered with synthetic grass. It was placed on a field behind the Stedelijk Museum, in Amsterdam, functioning both as a visual enigma and as something that passersby could play with interactively. A ludic feature of this pneumatic sculpture was the seesaw effect that resulted when a number of people sat on it. It was one of the urban interventions in Sigma Projects’ Six Events in Amsterdam.