Baile Zhang, an assistant professor of physics at Nanyang Technological University in Singapore, has used the light-bending qualities of calcite - a cheap and abundant mineral that is a form of calcium carbonate - to create the first macroscopic invisibility cloak. Zhang originally came up with the technology in 2010. This short video clip is similar to what he recently demonstrated on stage at TED2013. He is placing a piece of calcite over a rolled-up Post-it note submerged in oil, making the pink tube appear to disappear. This research has applications in imaging, communication, and defense.