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