Parent State ID: 21
State Depth: 5
Action Taken: unstack(block_b, block_d)
Action Reasoning: Block C is clear, so the best next action is to place block D on block C, following the goal to stack all blocks neatly.
State Description: Block A is clear and still on block B. Block B has been removed from block D and is in the hand, not clear. Block C is clear and still on the table. Block D is now clear on the table. The hand is holding block B.
Action Path: ['unstack(block_b, block_c)', 'stack(block_b, block_d)', 'pick-up(block_a)', 'stack(block_a, block_b)', 'unstack(block_b, block_d)']

INACTIVE REASON: deactivated because diagram generation failed or invalid action chosen: 
