Current State ID: 22
Current State Description: The hand is holding block 'a'. Block 'b' is clear and remains on the table. Block 'c' is clear and remains on the table. Block 'd' is clear and remains on the table. The hand is no longer empty.

Child State ID: 28
Action Taken: stack(a, c)
State Description: The hand is empty. Block 'a' is on top of block 'c'. Block 'b' is clear and remains on the table. Block 'c' is supporting block 'a' and is on the table. Block 'd' is clear and remains on the table.

