It was designed and, rather delicately, built, by Tobias Toestesen, for Milan Design Week. The idea, taking the same basic transparent shape to create a larger construct, is to manipulate the light, using the Lego pieces to create shifting patterns and distortions.
Some eight thousand of the large half-cyclinder pieces are used in it's construction. Here is Toestesen at work building it:
You can see more images on Design Boom.
