An Israeli company has asked the United States Patent and Trademark Office for legal rights to a process for making a special kind of human cell. The company, Nano Dimension, says it uses a specialized 3-D printer to create an environment in which stem cells could grow into tissue. Stem cells can develop into many different kinds of cells in the body. They can also repair damaged tissues and organs. One kind, called induced pluripotent stem cells (IPS), are used to replace tissues lost to disease or injury. The term 3-D is short for three dimensional. That means an object has length, width and height. In 3-D printing, 3-D models are first created as files on a computer. The printer then uses a material like plastic or metal to create physical objects. The process involves making one layer at a time until the objects reach full form. Usually this process is slow.