}
protected void makeWorld() {
world = new GridLimitedOptionsWorld(15, 18, cellwidth, cellheight);
Body landmark = new Phys2DBody( new StaticBox(cellwidth, cellheight), 10, true );
landmark.setLocation(4.5*cellwidth, 14.5*cellheight);
landmark.setType(Body.UNDEFINED);
world.addFixedBody(landmark);
landmark = new Phys2DBody( new StaticBox(cellwidth, cellheight), 10, true );
landmark.setLocation(4.5*cellwidth, 8.5*cellheight);
landmark.setType(Body.UNDEFINED);
world.addFixedBody(landmark);
landmark = new Phys2DBody( new StaticBox(cellwidth, cellheight), 10, true );
landmark.setLocation(10.5*cellwidth, 8.5*cellheight);
landmark.setType(Body.UNDEFINED);
world.addFixedBody(landmark);
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);