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

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