Anti-aliasing needed to suppress the self-gravity. A cross section of the Gaussian density Eq. (14) with one-pixel variance about (blue) points in the middle grid cell, representing a 12th order weight function. We only account for the pixels inside a sphere with a radius of 4s (dashed circles). This results in a domain of 251 cells (inside the contours). The linear motion of a point particle across the middle cell (left to top right) shows that the simulated density changes smoothly between panels.