I'm looking for down-to-earth examples of self-dual koszul algebras. That is, algebras for which the ext algebra is isomorphic to the algebra itself. There is an example in the beginning of the BGS article (link http://www.ams.org/journals/jams/1996-9-02/S0894-0347-96-00192-0/S0894-0347-96-00192-0.pdf) which I unfortunately don't understand since I don't know any Lie theory.
Are there simpler examples? Ideally ones you can write down in generators & relations form.