landmark = new Phys2DBody( new StaticBox(cellwidth, cellheight), 10, true );
landmark.setLocation(10.5*cellwidth, 2.5*cellheight);
landmark.setType(Body.UNDEFINED);
world.addFixedBody(landmark);
rf = new GridRewardFunction();
world.setRewardFunction(rf);
world.addCollisionListener(rf);
GoalBody goal = new GoalBody(525, 125);
goal.setReward(0);