String is a long flexible tool made from fibers twisted together into a single strand, or from multiple such strands which are in turn twisted together. String is used to tie, bind, or hang other objects. It is also used as a material to make things, such as textiles, and in arts and crafts. String is a simple tool, and its use by humans is known to have been developed tens of thousands of years ago. String may also be a component in other tools, and in devices as diverse as weapons, musical instruments, and toys. The ubiquity of string as a tool has led to conceptual and scientific uses of the term, including strings in computer science, cosmic strings, and string theory.