Illustration of the numerical scheme for the DM-baryon interactions. The numerical particles are shown together with the physical particles they represent. The velocities of the physical particles are indicated by small arrows. The different stages in treating the interaction between baryons and DM for a single pair of numerical particles are illustrated from the left to the right. As shown here, the case of an interaction between a numerical baryonic particle and a numerical DM particle involves a change in their bulk motion and heating of the baryons. Finally, we note that here we also illustrate the case where the baryons consist of two species, but only one interacts with DM.