There are 4 shapes on a 3x3 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 (0, 1)
Distance from target shape to purple square at (1, 2): 2
Distance from target shape to pink right_triangle at (2, 0): 3
Distance from target shape to cyan rectangle at (2, 1): 2
Closest shape is the purple square at (1, 2) with distance 2</think>

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