Current State ID: 33
Current State Description: Block 'a' is on top of block 'd', and both blocks 'b' and 'c' remain clear and on the table. The hand is now empty. In the diagram, block 'a' is stacked on block 'd', and the hand is no longer holding anything.

Child State ID: 41
Action Taken: pick-up(b)
State Description: Block 'a' is on top of block 'd', block 'c' is clear and on the table, and block 'b' is held in the hand. The hand is no longer empty. In the diagram, block 'b' is lifted from the table, and the hand is holding block 'b'.

