Current State ID: 5
Current State Description: Block `a` is held by the hand and is no longer on block `c`. Block `c` is clear and on top of block `b`. Block `b` is on the table. Block `d` is on the table and clear. The hand is holding block `a`.

Child State ID: 6
Action Taken: stack(a, d)
State Description: Block `a` is now on top of block `d` and is clear. Block `d` is on the table but is no longer clear because block `a` is on it. Block `c` remains clear and on top of block `b`. Block `b` is on the table. The hand is empty.

Child State ID: 7
Action Taken: put-down(a)
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.

