There are 5 shapes on a 5x5 grid. Which shape is closest to the red 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: red right_triangle at (3, 0)
Distance from target shape to green right_triangle at (3, 3): 3
Distance from target shape to blue rectangle at (0, 0): 3
Distance from target shape to purple rectangle at (1, 2): 4
Distance from target shape to brown square at (2, 1): 2
Closest shape is the brown square at (2, 1) with distance 2</think>

<answer>(2, 1)</answer>