Current State ID: 6
Current State Description: There are four blocks: a, b, c, and d. The hand is holding block d. Block a is on the table and clear. Block b is on the table and clear. Block c is on the table and clear. Block d is no longer on block a.

Child State ID: 8
Action Taken: stack(d, b)
State Description: The hand is empty. Block a is on the table and clear. Block b is on the table with block d on top of it. Block c is on the table and clear. Block d is on block b and is clear.

Child State ID: 9
Action Taken: put-down(d)
State Description: There are four blocks: a, b, c, and d. The hand is empty. Block a is on the table and clear. Block b is on the table and clear. Block c is on the table and clear. Block d is on the table and clear.

