[plt-scheme] Diagrams

Here's a thought -- there must be *some* reason David Gries refers to a
certain style of diagram as "flAwcharts" (let the flamage begin :-)

For Richard in particular:  Some years back I worked for an organization
that was producing a highly secure OS, under DoD contract.  While the
initial, proof-of-concept project sort of required some
Nassi-Schneiderman chart mumblage, subsequent revisions and follow-on
contracts quietly dropped them.  The customer was quite content with
good design docs + formal top-level specifications + detailed top-level
specs + formal security policy model.

 -- Bill Wood