There are 3 shapes on a 8x8 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 (3, 5)
Distance from target shape to pink square at (5, 6): 3
Distance from target shape to brown square at (3, 7): 2
Closest shape is the brown square at (3, 7) with distance 2</think>

<answer>(3, 7)</answer>