This section introduces [B/D] techniques that are a little more advanced
than those that we have seen already. In particular we consider using
[B/D] to transform some of our inputs and outputs in ways which allow a
more detailed analysis of the example. If you wish only to generate the
output referred to in part ii, simply type the commands
that are shown below in a bold typeface preceeded with the [B/D] prompt
BD>, and ignore the commentary!