+ ::
+
+ sage: A1 = OctonionMatrixAlgebra(1,QQ)
+ sage: A2 = OctonionMatrixAlgebra(1,QQ)
+ sage: cartesian_product([A1,A2])
+ Module of 1 by 1 matrices with entries in Octonion algebra with
+ base ring Rational Field over the scalar ring Rational Field (+)
+ Module of 1 by 1 matrices with entries in Octonion algebra with
+ base ring Rational Field over the scalar ring Rational Field
+