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