Imagine a team of mischievous  technicians that would invest the underground train and change its white neons in one night to replace them by coloured ones. Imagine the surprise of the users in the morning when they discover this playful change.  Colours get reflected and move into the compartments to create contrasting and futuristic atmospheres, and give a new idea of public transportation (Fête des Lumières de Lyon in 2004 and 2006)