Current State ID: 20
Current State Description: Block `a` is on the table and clear. Block `b` is on the table and supports block `c`. Block `c` is on block `b` and is clear. Block `d` is on the table and clear. The hand is empty.

Child State ID: 30
Action Taken: pick-up(d)
State Description: Block `a` is on the table and clear. Block `b` is on the table and supports block `c`. Block `c` is on block `b` and is clear. Block `d` is held by the hand. The hand is not empty.

