There are 3 shapes on a 4x4 grid. Which shape is closest to the purple 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: purple right_triangle at (0, 1)
Distance from target shape to pink trapezoid at (1, 2): 2
Distance from target shape to gray rectangle at (2, 3): 4
Closest shape is the pink trapezoid at (1, 2) with distance 2</think>

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