ter in the chain, then through the second filter, and so on, and eventually reaches the Device at the end of the chain. When a chain is used for input, data travels in the opposite direction, beginning at the Device at the end of the chain, then passing through the filters in reverse order. By default, if the Device at the end of a chain is popped or if a chain is complete when it is destroyed, all the filters and devices in the chain are closed using the function <A HREF='../functions/close.html'><CODE>clo