There are 3 shapes on a 8x8 grid. Which shape is closest to the purple trapezoid 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 trapezoid at (6, 7)
Distance from target shape to pink trapezoid at (3, 6): 4
Distance from target shape to red square at (5, 1): 7
Closest shape is the pink trapezoid at (3, 6) with distance 4</think>

<answer>(3, 6)</answer>