The stage show K└, a production by the Canadian circus troupe Cirque du Soleil, was directed by Robert Lepage. This production revolves around a storyline, which is quite unusual as Cirque productions are generally theme based. The projected images follow the course of this story and serve as virtual scenery.
It took more than two years of work leading up to the premiere in 2004 to develop the interactive projections that are generated by pure mathematical and physical calculations in real-time. The projections were revised slightly in 2012 and adapted to use more current technology. The advancement of computer technology made some image calculations possible that were not achievable at the time of the premiere of the show.
Among the projections are a rain of arrows, thundery clouds, sea waves, an underwater scene, stone and ice landscapes, glowing lianas of a forest, and caustics of an artificial water surface. Some of the original images can be seen in the 3D film production Cirque du Soleil: Worlds Away.