 (0.0,00.0)[![Time evolution of the density distribution in the innermost $000~\rm{AU}$ of the gas cloud shortly before and shortly after the formation of the first protostar at $t_{\rm{SF}}$. Only gas at densities above $00^{00}~\rm{cm}^{-0}$ is plotted. The dynamical timescale at a density of $n=00^{00}~\rm{cm}^{-0}$ is of the order of $00$ years. Dark dots indicate the location of protostars as identified by sink particles forming at $n\ge 00^{00}~\rm{cm}^{-0}$. Note that without usage of sink particles to identify collapsed protostellar cores one would not have been able to follow the build-up of the protostellar cluster beyond the formation of the first object. There are $000$ protostars when we stop the calculation at $t=t_{\rm{SF}}+000~\rm{yr}$. They occupy a region roughly a hundredth of the size of the initial cloud (see Clark et al. 0000).](f0