The filter in use
A filter receives a wires input that tells it to put certain things through. If the input is a Boolean 0, it will put all the items in the left output, the opposite for 1. If the wires input is an item, it will put the items that match exactly going through the front output. It will put the others out the right output. If the wire input is nothing (nil) the filter will stop operating; if this is undesirable you can prevent it by using logic gates.