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

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