  The Menger sponge is a three-dimensional cube that comprises a self-similar,
fractal domain and a non-fractal domain, both of which are continuous. Thus it
is a useful heuristic model for natural and engineered fractal systems. For
this purpose the effective transport coefficient associated with the transport
properties (e.g., electrical conductivity, thermal conductivity) of the sponge
is derived. Comparison is made to the Sierpinski sponge.
