Author response image 2. At cell division, the daughter cell equilibrates by half a cell radius in one time unit, which is of order 1/1000 the generation time.

Here, we show how a new cell (in blue) reaches equilibrium (in red). Cell division happens at time 0. At time 5, the next consecutive division happens in the system (not shown). The systems consists of 200 cells placed on a hollow sphere which is the initial condition in our organoid simulations (Figure 5). A new cell is introduced half a cell radius in a random direction away from the mother cell. The red line is the mean distance from the mother cell to all it’s neighbor cells at t = 1000. The generation time is intermediate (Figure 5A).