There are 4 shapes on a 3x3 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 (0, 2)
Distance from target shape to brown square at (2, 0): 4
Distance from target shape to green right_triangle at (1, 1): 2
Distance from target shape to purple rectangle at (2, 1): 3
Closest shape is the green right_triangle at (1, 1) with distance 2</think>

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