  In this work, we address a planar non-prehensile sorting task. Here, a robot
needs to push many densely packed objects belonging to different classes into a
configuration where these classes are clearly separated from each other. To
achieve this, we propose to employ Monte Carlo tree search equipped with a
task-specific heuristic function. We evaluate the algorithm on various
simulated and real-world sorting tasks. We observe that the algorithm is
capable to reliably sort large numbers of convex and non-convex objects, as
well as convex objects in the presence of immovable obstacles.
