Previous work by Behringer's group [25,26] utilized an annular gap, as opposed to a rectangular box, to remove the frictional in fluence of a set of walls and focus on heaping and convection in the azithumal direction. In our work, tests without sandpaper (smooth walls) did not demon-strate convection and dynamics were very slow, on the order of hours.With sandpaper, the system reached a statistical steady-state on the
order of minutes.