Parent State ID: 18
State Depth: 7
Action Taken: pick-up(a)
Action Reasoning: To achieve the goal state, we need to stack block a on block c. Since both blocks are clear and the hand is empty, the best action is to pick up block a.
State Description: The hand is holding block a. Block c is on the table and clear. Block b is on the table with block d on top of it. Block d is on block b and is clear. Block a is no longer clear or on the table. The diagram now shows block a being held by the hand.
Action Path: ['unstack(c, d)', 'put-down(c)', 'unstack(d, a)', 'stack(d, b)', 'pick-up(c)', 'put-down(c)', 'pick-up(a)']
