Signal Festival 2013 featured “Pipeline”, a digital art by Vojmír Křupka in Prague.
An intangible green line of a rotating laser beam creating a cylindrical shape in the space above the heads of pedestrians; reflected in mirrors it moves along a slightly bending street. Moving along the street it ends in a circle projected on the front of a transversal street.
Programme information from Signal Festival. Short excerpt quoted for reference; see the original page for full text, images and credits.