(unstack orange red robot)
(put-down orange robot)
(unstack red yellow robot)
(put-down red robot)
(unstack yellow green robot)
(put-down yellow robot)
(unstack green blue robot)
(put-down green robot)
(unstack blue purple robot)
(put-down blue robot)
(pick-up purple robot)
(stack purple orange robot)
(pick-up green robot)
(stack green blue robot)
(pick-up red robot)
(stack red yellow robot)