+0. Add tests for orthogonality in the Peirce decomposition.
+
1. Add CartesianProductEJA.
2. Check the axioms in the constructor when check != False?
3. Add references and start citing them.
4. Implement the octonion simple EJA.
+
+5. Factor out the unit-norm basis (and operator symmetry) tests once
+ all of the algebras pass.