There are 4 shapes on a 9x9 grid. Which shape is closest to the gray right_triangle in terms of Manhattan distance? The final answer is the grid position of the closest shape like (row_index, column_index).
<think>Target shape: gray right_triangle at (7, 4)
Distance from target shape to purple rectangle at (3, 6): 6
Distance from target shape to green square at (5, 6): 4
Distance from target shape to blue rectangle at (0, 5): 8
Closest shape is the green square at (5, 6) with distance 4</think>

<answer>(5, 6)</answer>