The best way to solve this is by giving a visual idea of the glass ornaments. so We will have letter G represent Green, O for Orange, B for Brown, P for Purple. Sample 1:G,O,B,P Sample 2:G,P,O,B Sample 3:P,G,O,B Sample 4:O,G,P,B Sample 5:G,O,P,B This is what you can do this should be the right amount of ways to arrange them.