Example Database

I am rather new to PostgreSQL.What I am looking for ist this:

An example database that demonstrates the usage of all the core
PostgreSQL features. It is one thing to read extensive documentation,
but it is much more intuitive for me to see an example database, that
demonstrates the whole thing interacting. I mean, not just the basic
elements, but an optimized (and maybe nicely documented) database
getting the best out of views, triggers, indices, rules, stored
procedures and so on - maybe even a reference database from the
PostgreSQL developers themselves?

Have been searching for some hours now, but did not succeed. Maybe I am
just being blind.

Thanx for any hints!

Regards, Erwin Brandstetter