Attempt Number: 3
Error Message: Action not unique compared to other actions chosen from this state before. Choose a new action

Action Reasoning:
To progress towards the goal state, we need to stack block `a` on block `d`, which is clear. This will match the desired stack formation of blocks `a`, `d`, and `b`.

New State Description:
Block `a` is on block `d` and is clear. Block `b` is on the table and is not clear, as it supports block `d`. Block `c` is on the table and is clear. Block `d` is on block `b` and is not clear, as it supports block `a`. The hand is empty.

Action Chosen:
stack(a, d)
