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

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