There are 5 shapes on a 5x5 grid. Which shape is closest to the brown right_triangle in terms of Manhattan distance? The final answer is the grid position of the closest shape like (row_index, column_index).
<think>Target shape: brown right_triangle at (3, 1)
Distance from target shape to blue square at (2, 3): 3
Distance from target shape to purple rectangle at (4, 1): 1
Distance from target shape to pink square at (3, 2): 1
Distance from target shape to green right_triangle at (0, 0): 4
Closest shape is the purple rectangle at (4, 1) with distance 1</think>

<answer>(4, 1)</answer>