Parent State ID: 6
State Depth: 4
Action Taken: put-down(d)
Action Reasoning: To progress towards the goal state, block 'd' should be placed on block 'b'. First, put down block 'd' on the table to free the hand, then pick up block 'b' to stack 'd' on it.
State Description: There are four blocks: a, b, c, and d. The hand is empty. Block a is on the table and clear. Block b is on the table and clear. Block c is on the table and clear. Block d is on the table and clear.
Action Path: ['unstack(c, d)', 'put-down(c)', 'unstack(d, a)', 'put-down(d)']
