The silk yarn is then processed into silk. A base colour is chosen which forms the WARP. The warp is the lenth of fabric fed through the silk machine. As the silk passes through the WEFT weaves the various alternate colours through to form the texture and pattern of the silk. In years gone by this was all done manually but today, with computers as good as they are, this tecnhique can be managed, in part, by computer generated opening and closing of valves which work in a similar technique to a piano which plays sheet music.