Apple Shake 4 - Manual (Page 234)

234 Chapter 7 Using the Node View
You can also drag a noodle from an input knot to the output knot of a different node.
For example, you can drag a noodle from the Over1 node to the moon node.
On the other hand, you can drag as many connections from a node’s output as you
want. For example, you can connect a FileIn node’s output knot to several nodes. This
creates multiple separate branches of image processing, which can be recombined
later on in the tree.