One or two players try to swat a swarm of flies against a virtual window using real flyswatters. The “window” is a custom multitouch Plexiglas surface at the back side of which there is a projector, several IR spotlights and an IR camera tracking blobs touching the surface. Additionally, in front of the window there are distance and motion sensors the readings of which influence the behavior of the flies (when no one is near, or when there is no motion flies will tend to stay still, rapid motion will arouse them, etc.).