There are 5 shapes on a 4x4 grid. Which shape is closest to the brown square 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 square at (1, 3)
Distance from target shape to red rectangle at (1, 2): 1
Distance from target shape to green right_triangle at (2, 1): 3
Distance from target shape to yellow rectangle at (3, 1): 4
Distance from target shape to orange trapezoid at (1, 0): 3
Closest shape is the red rectangle at (1, 2) with distance 1</think>

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