I found 31-year-old Zhang in the auditorium, watching other TED Fellows talk. He told me the cloak is made out of two pieces of calcite, or optical crystals - found in nature - that are cemented together. The calcite bends light and suppresses shadows, creating the effect of, well, nothingness. When I asked him what his big plans were with this reality-bending invention, he said it had no purpose. He just created it for fun. He does, however, plan to make it bigger. How big? "As large as possible." The idea came to him in 2010, and today was the first time he's shown it to a live audience.