Parent State ID: 16
State Depth: 7
Action Taken: stack(d, b)
Action Reasoning: To achieve the goal state, we need to have block `d` on block `b` first. The path is clear to achieve this, as block `d` is clear and block `b` is suitable for having a block stacked upon it. Thus, the next logical action is to pick up `d` and stack it on `b`.
State Description: Block `a` is on the table and clear. Block `b` is on the table and not clear, holding block `d`. Block `c` is on block `b` and clear under block `d`. 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)', 'unstack(c, b)', 'stack(c, b)', 'stack(d, b)']

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