Hole geometry.

<p>Results for colonies grown at the bottom of a square hole in an agar surface 0.4 mm deep. Results for holes 0.2 mm deep are not shown as they are similar. The colony growth (top left) is mildly dependent upon the width of the hole with wider holes growing slightly more quickly. The relative fraction of acetate (bottom left) utilizers in the population grow with time until the wall the colony reaches the wall and a burst of glucose utilizers are grown until the colony on the wall is thick enough to begin producing acetate utilizers once again. The confinement leads to larger fraction of acetate utilizers than seen on flat surfaces. Snapshots of population volume fractions (top middle and right) and chemical concentrations (top middle and right) after 40 hours of growth. Further, a large build-up in acetate concentration (bottom middle; units of mM) inside the hole is apparent while nothing interesting occurs with the glucose concentration (bottom right; units of mM).