  We present a code to generate mock observations of 21 cm intensity mapping
experiments. The emphasis of the code is on reducing the computational cost of
running a full-blown simulation, trading computational time for accuracy. The
code can be used to generate independent realizations of the cosmological
signal and foregrounds, which are necessary, for instance, in order to obtain
realistic forecasts for future intensity mapping experiments. The code is able
to reproduce the correct angular and radial clustering pattern for the
cosmological signal, including redshift-space distortions, lightcone evolution
and bias. Furthermore, it is possible to simulate a variety of foregrounds,
including the potentially problematic polarized synchrotron emission.
