There are 2 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, 7)
Distance from target shape to gray rectangle at (4, 0): 11
Closest shape is the gray rectangle at (4, 0) with distance 11</think>

<answer>(4, 0)</answer>