Current State ID: 80
Current State Description: Block A is on the table and clear. Block B is held by the hand and not clear. Block C is on the table and not clear, with block D stacked on it. Block D is on block C and clear. The hand is holding block B, and is not empty.

Child State ID: 81
Action Taken: stack(block_b, block_d)
State Description: Block A is on the table and clear. Block B is on block D and clear. Block C is on the table and not clear, with block D stacked on it. Block D is on block C and not clear. The hand is empty.

