Current State ID: 43
Current State Description: Block `a` is held by the hand and not clear. Block `b` is on the table and not clear, as it supports block `d`. Block `c` is on the table and clear. Block `d` is on block `b` and clear. The hand is holding block `a`.

Child State ID: 49
Action Taken: stack(a, d)
State Description: Block `a` is on block `d` and clear. Block `b` is on the table and not clear, as it supports block `d`. Block `c` is on the table and clear. Block `d` is on block `b` and not clear, as it supports block `a`. The hand is empty.

