Parent State ID: 1
State Depth: 2
Action Taken: stack(blockD, blockC)
Action Reasoning: The hand is holding block D, and to reach the goal state, we need to stack block D on block C. This action will begin forming the desired stack structure.
State Description: Block A is on the table and clear. Block B is on block C and clear. Block C is on the table and supports block B and block D. Block D is on block C and clear. The hand is empty and no longer holding block D.
Action Path: ['pick-up(blockD)', 'stack(blockD, blockC)']

INACTIVE REASON: action path invalid: The last action "stack(blockD, blockC)" is invalid because blockC is not clear (blockB is on blockC), violating the precondition for stacking. The current state's description and visualization are inconsistent with the actions taken, as blockB should not be clear if it is on blockC.
