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