There are 3 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, 5)
Distance from target shape to purple rectangle at (5, 0): 7
Distance from target shape to blue rectangle at (4, 6): 4
Closest shape is the blue rectangle at (4, 6) with distance 4</think>

<answer>(4, 6)</answer>