Current State ID: 16
Current State Description: The hand is holding block 'a'. Block 'a' is no longer on the table and not clear. Blocks b, c, and d remain on the table and clear.

Child State ID: 22
Action Taken: stack(a, c)
State Description: The hand is now empty. Block 'a' is on block 'c' and is clear. Block 'c' is no longer clear. Blocks b and d remain on the table and clear.

Child State ID: 23
Action Taken: stack(a, c)
State Description: The hand is empty. Block 'a' is on block 'c', making block 'a' not clear. Blocks 'b' and 'd' remain on the table and clear. Block 'c' is no longer clear as it supports block 'a'.

