Parent State ID: 20
State Depth: 5
Action Taken: unstack(block_b, block_d)
Action Reasoning: To move towards the goal, block D should be placed on block C. First, we need to clear block B from block D, so I will unstack block B from block D.
State Description: Block A is on the table and clear. Block B is in the hand and not clear. Block C is on the table and clear. Block D is on the table and clear. The hand is holding block B.
Action Path: ['unstack(block_b, block_c)', 'stack(block_b, block_d)', 'unstack(block_b, block_d)', 'stack(block_b, block_d)', 'unstack(block_b, block_d)']

INACTIVE REASON: action path invalid: The last action `unstack(block_b, block_d)` is invalid because its preconditions are not met: `block_b` is not on `block_d`, `block_b` is not clear, and the hand is not empty. However, the current state's description and visualization are accurate with respect to the sequence of actions taken.
