There are 5 shapes on a 8x8 grid. Which shape is closest to the purple 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: purple rectangle at (3, 5)
Distance from target shape to blue trapezoid at (4, 7): 3
Distance from target shape to brown right_triangle at (3, 0): 5
Distance from target shape to gray trapezoid at (2, 1): 5
Distance from target shape to cyan trapezoid at (0, 5): 3
Closest shape is the blue trapezoid at (4, 7) with distance 3</think>

<answer>(4, 7)</answer>