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