  A method to evaluate spin networks for (2+1)-dimensional quantum gravity is
given. We analyse the evaluation of spin networks for Lorentzian, Euclidean and
a new limiting case of Newtonian quantum gravity. Particular attention is paid
to the tetrahedron and to the study of its asymptotics. Moreover, we propose
that all this technique can be extended to spin networks for quantum gravity in
any dimension.
