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 (0, 3)
Distance from target shape to purple right_triangle at (3, 0): 6
Distance from target shape to brown square at (2, 0): 5
Distance from target shape to cyan right_triangle at (1, 0): 4
Closest shape is the cyan right_triangle at (1, 0) with distance 4</think>

<answer>(1, 0)</answer>