There are 4 shapes on a 7x7 grid. Which shape is closest to the purple 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: purple square at (1, 5)
Distance from target shape to yellow square at (2, 3): 3
Distance from target shape to blue square at (6, 5): 5
Distance from target shape to orange trapezoid at (6, 4): 6
Closest shape is the yellow square at (2, 3) with distance 3</think>

<answer>(2, 3)</answer>