There are 4 shapes on a 7x7 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, 1)
Distance from target shape to pink trapezoid at (1, 6): 7
Distance from target shape to red square at (2, 4): 4
Distance from target shape to brown trapezoid at (4, 1): 1
Closest shape is the brown trapezoid at (4, 1) with distance 1</think>

<answer>(4, 1)</answer>