There are 4 shapes on a 8x8 grid. Which shape is closest to the blue 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: blue rectangle at (3, 2)
Distance from target shape to gray rectangle at (5, 1): 3
Distance from target shape to brown rectangle at (7, 3): 5
Distance from target shape to green rectangle at (6, 0): 5
Closest shape is the gray rectangle at (5, 1) with distance 3</think>

<answer>(5, 1)</answer>