  We give a status report on the hadronic light-by-light scattering
contribution to the muon's anomalous magnetic moment from the Dyson-Schwinger
approach. We discuss novel, model-independent properties of the light-by-light
amplitude: we give its covariant decomposition in view of electromagnetic gauge
invariance and Bose symmetry, and we identify the relevant kinematic regions
that are probed under the integral. The decomposition of the amplitude at the
quark level and the importance of its various diagrams are discussed and
related to model approaches.
