Revive v0.4.5's diagram style #104
Description
v0.4.5 had a diagram generator for classic structures, as can be seen here.
This was good. It worked. It was useful. It made things easy to explain.
It was discarded due to not being general enough to be able to illustrate all possible structures.
Perhaps there is a way to generalize it, and even if there is not, perhaps it is worth reviving for the specific sub-set of cases when it can be used as-is.