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

<answer>(3, 1)</answer>