Current State ID: 31
Current State Description: The hand is holding block a. Block c is on the table and clear. Block b is on the table with block d on top of it. Block d is on block b and is clear. Block a is no longer clear or on the table. The diagram now shows block a being held by the hand.

Child State ID: 41
Action Taken: stack(a, c)
State Description: The hand is now empty. Block 'a' is on block 'c', and block 'c' is no longer clear. Block 'b' is on the table with block 'd' on top of it, and block 'd' is clear. The diagram now shows block 'a' on block 'c'.

Child State ID: 42
Action Taken: stack(a, c)
State Description: The hand is empty. Block a is stacked on block c. Block c is clear, on the table, and supporting block a. Block b is on the table with block d on top of it. Block d is on block b and is clear.

