There are 5 shapes on a 5x5 grid. Which shape is closest to the yellow rectangle in terms of Manhattan distance? The final answer is the grid position of the closest shape like (row_index, column_index).
<think>Target shape: yellow rectangle at (2, 1)
Distance from target shape to blue trapezoid at (1, 4): 4
Distance from target shape to gray square at (3, 1): 1
Distance from target shape to purple right_triangle at (2, 4): 3
Distance from target shape to pink rectangle at (1, 1): 1
Closest shape is the gray square at (3, 1) with distance 1</think>

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