Current State ID: 7
Current State Description: Block `a` is now on the table and clear. Block `b` is on the table and supports block `c`. Block `c` is on block `b` and is clear. Block `d` is on the table and clear. The hand is empty.

Child State ID: 10
Action Taken: unstack(c, b)
State Description: Block `a` is on the table and clear. Block `b` is on the table and clear. Block `c` is in the hand and no longer on block `b`. Block `d` is on the table and clear. The hand is holding block `c`.

Child State ID: 11
Action Taken: pick-up(d)
State Description: Block `a` is on the table and clear. Block `b` is on the table and supports block `c`. Block `c` is on block `b` and is clear. Block `d` is held by the hand. The hand is not empty.

