Parent State ID: 20
State Depth: 7
Action Taken: stack(d, b)
Action Reasoning: To build towards the goal configuration, stack block `d` onto block `b`, because block `b` should support block `d` in the goal state and both are in the correct place and currently clear.
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 no longer clear. Block `d` is on block `b` and 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)', 'stack(d, b)']

INACTIVE REASON: deactivated because diagram generation failed or invalid action chosen: Preconditions for stacking are not met; the hand is not holding `d` and `b` is not clear.
