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

<answer>(2, 1)</answer>