There are 3 shapes on a 5x5 grid. Which shape is closest to the red 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: red square at (4, 2)
Distance from target shape to blue rectangle at (3, 1): 2
Distance from target shape to green square at (1, 4): 5
Closest shape is the blue rectangle at (3, 1) with distance 2</think>

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