If you enjoy these, you should check out some of the installation pieces by Olafur Eliasson. His oeuvre is more about playing with/exploiting perception -- one of my favorite pieces was a part of his exhibit at the Chicago MCA in summer 2009, which was a dark room with a central illuminated waterfall. The combination of a single reference point coupled with a totally matte darkness at the periphery meant that every step someone took that wasn't directly towards the waterfall resulted in them reflexively extending their hands to avoid a (possible) collision. Really exceptional stuff.