We can also find the individuals that John believes can fly.
To see how to do this, first find the nodes that represent Cassie's
beliefs about John's beliefs; this can be done using
(find agent John act believe). Then use this to find the nodes that are
objects of John's beliefs about who can fly: (find object-
(find agent John act believe) ability fly). Finally, use this
to find the objects that John believes can fly:
