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