We have Graphviz enabled on this forum, so in addition to the cool Mermaid charts you can also do more interesting things with Graphviz.
Here is an example:
The above is generated with text like this:
[graphviz engine=circo]
graph {
a -- b;
b -- c;
c -- d;
d -- e;
e -- g;
a -- g;
a -- c;
a -- d;
a -- e;
b -- d;
b -- e;
b -- g;
c -- e;
c -- g;
d -- g;
}
[/graphviz]
More details on the plugin here: Graphviz Plugin - plugin - Discourse Meta . Also, check out the graphviz gallery page for more interesting examples of what you can do with it.