Attempt Number: 4
Error Message: The action and resulting child state have already been explored.

Action Reasoning:
The robot is currently at tile_1-1 and holding a black paint gun. According to the goal state, tile_0-0 should be painted black. The robot needs to move to tile_1-0 to paint tile_0-0. The shortest path to achieve this is to move left from tile_1-1 to tile_1-0. This aligns with the logical conclusion that if the highest robot is not at tile_1-0, it should move there first.

New State Description:
Robot1 is now at tile_1-0, holding a black paint gun. Tile_1-1 is clear, and tile_1-0 is occupied by the robot.

Action Chosen:
left(robot1, tile_1-1, tile_1-0)
