  A rudimentary, one-zone, closed-box model for inhomogeneous chemical
evolution is offered as an alternative reference than the Simple model in the
limit of no mixing. The metallicity distribution functions (MDFs) of Galactic
halo and bulge stars can be matched by varying a single evolutionary parameter,
nQ. Q is the filling factor of contaminating regions and n is the number of
star-forming generations. Therefore, Q and n have equivalent roles, and
combinations of n and Q yield systems with different metallicities at any given
age. The model also revises interpretation of observed MDFs. Unevolved systems
probe the parent distribution of metal production f(z), for example, the
high-metallicity tail of the halo distribution agrees with a power-law f(z).
