There are 4 shapes on a 8x8 grid. Which shape is closest to the brown rectangle in terms of Manhattan distance? The final answer is the grid position of the closest shape like (row_index, column_index).
<think>Target shape: brown rectangle at (6, 4)
Distance from target shape to yellow rectangle at (5, 1): 4
Distance from target shape to pink rectangle at (7, 4): 1
Distance from target shape to orange right_triangle at (4, 7): 5
Closest shape is the pink rectangle at (7, 4) with distance 1</think>

<answer>(7, 4)</answer>