There are 5 shapes on a 9x9 grid. Which shape is closest to the purple 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: purple right_triangle at (8, 8)
Distance from target shape to red trapezoid at (8, 4): 4
Distance from target shape to pink rectangle at (3, 8): 5
Distance from target shape to blue square at (1, 3): 12
Distance from target shape to gray rectangle at (8, 7): 1
Closest shape is the gray rectangle at (8, 7) with distance 1</think>

<answer>(8, 7)</answer>