HStack cubes = new HStack();
cubes.setLayoutMargin(20);
cubes.setMembersMargin(40);
cubes.setLayoutAlign(Alignment.CENTER);
cubes.addMember(new DragPiece("cube_blue.png", "b"));
cubes.addMember(new DragPiece("cube_yellow.png", "y"));
cubes.addMember(new DragPiece("cube_green.png", "g"));
HStack edges = new HStack();
edges.setMembersMargin(20);