There are 4 shapes on a 4x4 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 yellow right_triangle at (3, 3): 5
Distance from target shape to cyan trapezoid at (1, 3): 3
Distance from target shape to purple rectangle at (2, 3): 4
Closest shape is the cyan trapezoid at (1, 3) with distance 3</think>

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