There are 3 shapes on a 7x7 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 (5, 1)
Distance from target shape to orange square at (4, 3): 3
Distance from target shape to green rectangle at (3, 1): 2
Closest shape is the green rectangle at (3, 1) with distance 2</think>

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