Parent State ID: 30
State Depth: 8
Action Taken: stack(d, b)
Action Reasoning: Since the goal is to have block `d` on top of block `b` and they're both clear, the next best action is to stack block `d` onto block `b`.
State Description: Block `a` is on the table and clear. Block `b` is on the table and supports block `d`. Block `c` is on block `b` and is clear. Block `d` is on block `b` and is not clear. The hand is empty.
Action Path: ['unstack(d, a)', 'put-down(d)', 'unstack(a, c)', 'put-down(a)', 'pick-up(d)', 'put-down(d)', 'pick-up(d)', 'stack(d, b)']

INACTIVE REASON: deactivated because diagram generation failed or invalid action chosen: Block b is not clear, violating the precondition for stacking.
