cubes.addMember(new DragPiece("cube_yellow.png", "y"));
cubes.addMember(new DragPiece("cube_green.png", "g"));
HStack edges = new HStack();
edges.setMembersMargin(20);
edges.addMember(new PieceBin("edges/blue/6.png", "b"));
edges.addMember(new PieceBin("edges/yellow/6.png", "y"));
edges.addMember(new PieceBin("edges/green/6.png", "g"));
edges.addMember(new PieceBin("edges/gray/6.png", "b", "y", "g"));
VStack main = new VStack();