If you ever watched a movie from or played a video game you have seen an invisible cloak in use. An invisible cloak is cloak that someone would put on and become invisible to naked eye. As much as this cloak is a futuristic sci-fi thing its actually being made in Germany. Tiemo Bueckmann, a researcher and PhD student in Karlsruhe Institute of Technology is making this happen. He invented a material in which is a matrix of long, thin, tiny cones. When someone applies pressure on these cones they collapse, and any object beneath becomes undetectable. It is a solid that acts like a liquid. However there are many complications. One is that the liquid can only hide a pea. Also you cannot use two by two matrix, you have to use there by three by three and only material on earth that can have that kind of matrix is liquid. It will take long time for Tiemo or other researchers to invent something for full human body and that is actually a solid, but the good news is that the research is happening.