//alternate between yellow pawn and green cube
if (tabSet.getTabs().length % 2 == 0) {
Tab tab = new Tab("Yellow", "pieces/16/pawn_yellow.png");
Img img = new Img("pieces/48/pawn_yellow.png", 48, 48);
tab.setPane(img);
tabSet.addTab(tab);
} else {
Tab tab = new Tab("Green", "pieces/16/cube_green.png");
Img img = new Img("pieces/48/cube_green.png", 48, 48);
tab.setPane(img);
tabSet.addTab(tab);