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