Ephemeral nodes

In PQL, ephemeral nodes exist only temporarily, or for a very short time. They can be created accidently by running a query like the one below, in which the node 4 has no existence outside of the query itself.

The pound # sign in /#id avoids accidently creating ephemeral nodes with the id function. In the example below, the ephemeral nodes of 4 exist only because the query points to them. They don't exist outside of the query.