There are 4 shapes on a 8x8 grid. Which shape is closest to the green 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: green square at (1, 0)
Distance from target shape to red rectangle at (3, 1): 3
Distance from target shape to cyan rectangle at (6, 7): 12
Distance from target shape to purple square at (4, 1): 4
Closest shape is the red rectangle at (3, 1) with distance 3</think>

<answer>(3, 1)</answer>