The title of this post refers to the tendency of algorithms in papers to have detailed explanation of every step except the most crucial one. Right now I am rediscovering this peculiar pleasure in structure generation.
As an example - or more as visual decoration - have this image:
which looks nice, but needs some explanation. The diagrams in boxes that look like parachutes (as one of my colleagues put it :) are simple representations of atoms connected by bonds. Each point is an atom, and a curved line connecting them is a bond.
These are grouped together by what structure they correspond to; which is shown on the right of each set of diagrams. What this shows, then, is the redundancy you get from a simple generator. If you connect all atoms like this:
for atomA in atoms:
for atomB in atoms greater than atomA:
You quickly get a very large number of isomorphic structures. And then your process runs out of memory, in my experience.
Oh, and the numbers below each graph are the sum of the indegree/outdegree (the degree?) of the that vertex - or the number of bonds the atom is in, in other words. This seems similar to the ideas behind Morgan numbers, which I now understand a bit better.