There are 6 shapes on a 9x9 grid. Which shape is closest to the blue 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: blue right_triangle at (8, 1)
Distance from target shape to brown right_triangle at (0, 1): 8
Distance from target shape to purple trapezoid at (6, 5): 6
Distance from target shape to pink right_triangle at (8, 5): 4
Distance from target shape to yellow rectangle at (3, 2): 6
Distance from target shape to green square at (4, 7): 10
Closest shape is the pink right_triangle at (8, 5) with distance 4</think>

<answer>(8, 5)</answer>