There are 5 shapes on a 4x4 grid. Which shape is closest to the gray 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: gray square at (3, 1)
Distance from target shape to pink trapezoid at (1, 1): 2
Distance from target shape to green square at (3, 2): 1
Distance from target shape to brown right_triangle at (1, 0): 3
Distance from target shape to orange rectangle at (0, 2): 4
Closest shape is the green square at (3, 2) with distance 1</think>

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