There are 4 shapes on a 4x4 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, 1)
Distance from target shape to gray rectangle at (3, 3): 2
Distance from target shape to cyan rectangle at (3, 2): 1
Distance from target shape to purple rectangle at (0, 2): 4
Closest shape is the cyan rectangle at (3, 2) with distance 1</think>

<answer>(3, 2)</answer>