Current State ID: 14
Current State Description: Block `a` is on block `d` and clear. Block `b` is in the hand and not clear. Block `c` is on the table and clear. Block `d` is on the table and supporting block `a`. The hand is holding block `b`.

Child State ID: 20
Action Taken: stack(b c)
State Description: Block `a` is on block `d` and clear. Block `b` is on block `c` and clear. Block `c` is on the table and supporting block `b`. Block `d` is on the table and supporting block `a`. The hand is empty.

