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