; total time: 0.04
; plan length: 20
(unstack b c)
(put-down b)
(unstack c a)
(put-down c)
(unstack a d)
(put-down a)
(pick-up c)
(stack c a)
(pick-up d)
(stack d c)
(unstack d c)
(put-down d)
(unstack c a)
(put-down c)
(pick-up a)
(stack a b)
(pick-up c)
(stack c a)
(pick-up d)
(stack d c)
