Parent State ID: 4
State Depth: 4
Action Taken: put-down(a)
Action Reasoning: To move towards the goal state, I will put down block `a` on the table, making the hand empty and leaving all blocks in states that conform to the goal structure.
State Description: Block `a` is on the table and clear. Block `b` is on the table supporting block `c`, which is clear. Block `c` is on block `b`. Block `d` is on the table and clear. The hand is empty.
Action Path: ['unstack(d a)', 'put-down(d)', 'pick-up(a)', 'put-down(a)']

INACTIVE REASON: deactivated because diagram generation failed or invalid action chosen: The action does not bring us closer to the goal state, as block `a` should be on block `d`, not on the table.
