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 (3, 0)
Distance from target shape to blue trapezoid at (1, 2): 4
Distance from target shape to purple rectangle at (1, 3): 5
Closest shape is the blue trapezoid at (1, 2) with distance 4</think>

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