Current State ID: 3
Current State Description: Block `d` is now on the table and clear. The hand is empty. Block `a` is clear and on top of block `c`. Block `c` is on top of block `b`. Block `b` is on the table.

Child State ID: 5
Action Taken: unstack(a, c)
State Description: Block `a` is held by the hand and is no longer on block `c`. Block `c` is clear and on top of block `b`. Block `b` is on the table. Block `d` is on the table and clear. The hand is holding block `a`.

