There are 4 shapes on a 8x8 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 (2, 7)
Distance from target shape to pink right_triangle at (6, 4): 7
Distance from target shape to gray rectangle at (2, 6): 1
Distance from target shape to blue square at (5, 5): 5
Closest shape is the gray rectangle at (2, 6) with distance 1</think>

<answer>(2, 6)</answer>