  We determine explicitly a rational even Drinfeld associator Q in a completion
of the universal enveloping algebra of the Lie superalgebra gl(1|1)^3. More
generally, we define a new algebra of trivalent diagrams that has a unique even
horizontal group-like Drinfeld associator P. The associator P is mapped to Q by
a weight system. As a result of independent interest, we show how O. Viro's
generalization Delta^1 of the multi-variable Alexander polynomial can be
obtained from the universal Vassiliev invariant of trivalent graphs. We
determine P by using the invariant Delta^1(T) of a planar tetrahedron T.
