Attempt Number: 4
Error Message: Action not unique compared to other actions chosen from this state before. Choose a new action

Action Reasoning:
Robot1 should move down to tile_2-1 and paint it black, as this aligns with the goal state, and the tile below is currently clear. This action will work towards completing the bottom row of tiles first, following the problem constraints.

New State Description:
Tile tile_0-1 is clear. Tile tile_0-2 is clear. Tile tile_0-3 is clear. Tile tile_1-1 is occupied by robot1 holding color black. Tile tile_1-2 is clear. Tile tile_1-3 is clear. Tile tile_2-1 is painted black. Tile tile_2-2 is painted white. Tile tile_2-3 is painted black. Robot1 is on tile_1-1, holding color black. Colors white and black are available for switching.

Action Chosen:
paint-down(robot1, tile_2-1, tile_1-1, black)
