Current State ID: 47
Current State Description: Block 'a' is on top of block 'b'. Block 'b' is on the table and supporting block 'a'. Block 'c' is on the table and clear. Block 'd' is held in the hand. The hand is not empty. The diagram would show block 'a' on block 'b', block 'c' on the table, and block 'd' held by the hand.

Child State ID: 51
Action Taken: stack(d, c)
State Description: Block 'a' is on top of block 'b'. Block 'b' is on the table and supporting block 'a'. Block 'c' is on the table and supporting block 'd'. Block 'd' is on top of block 'c' and clear. The hand is empty. The diagram would show block 'a' on block 'b', block 'c' on the table with block 'd' on top of it, and the hand empty.

