Felt from wool is the oldest textile. Fragments date from 6300 BCE. Animal fibers felt because there are overlapping scales on each strand of fiber. In the wet felting process layers of fibers are saturated with water. Soap may be added. This fulling process uses agitation by rolling, rubbing or pounding which strengthens and shrinks the fabric. Needle (dry) felting is done by poking the fibers with triangular needles which have downward-pointing barbs, causing the fibers to interlock.