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