Figure 6

An illustration of the calculation of the probability for two cells to be a distance d _c or less apart at a time t when they perform random walks from initial positions separated by a distance d ₀. Blue and orange dots show the initial positions of the cells. After a time t, each cell is located at a distance L from its original position at some point on the circle shown short-dashed (red) and long-dashed (blue), respectively. To be within a distance less than d _c, the cells need to be anywhere in the green rectangular region.