There are 3 shapes on a 6x6 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, 1)
Distance from target shape to pink square at (3, 3): 2
Distance from target shape to brown trapezoid at (5, 0): 3
Closest shape is the pink square at (3, 3) with distance 2</think>

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