Parent State ID: 1
State Depth: 2
Action Taken: stack(block_a, block_c)
Action Reasoning: We need to place block 'a' onto block 'c' directly. Currently, block 'a' is held by the hand, and block 'c' is the base and clear. The best action is to use the "stack" action to stack block 'a' on block 'c'.
State Description: Block 'a' is now on top of block 'c' and is clear because nothing is on it. Block 'c' is supporting block 'a'. Block 'b' remains on block 'c' and supports block 'd'. Block 'd' is clear. The hand is empty and no longer holding any block.
Action Path: ['unstack(block_a, block_d)', 'stack(block_a, block_c)']

INACTIVE REASON: deactivated because diagram generation failed or invalid action chosen: block_c is not clear, violating the precondition for stacking.
