There are 3 shapes on a 4x4 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 (2, 3)
Distance from target shape to green right_triangle at (3, 2): 2
Distance from target shape to pink right_triangle at (2, 1): 2
Closest shape is the green right_triangle at (3, 2) with distance 2</think>

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