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 (1, 4)
Distance from target shape to orange right_triangle at (4, 4): 3
Distance from target shape to gray right_triangle at (2, 4): 1
Distance from target shape to cyan trapezoid at (6, 7): 8
Distance from target shape to green trapezoid at (3, 6): 4
Closest shape is the gray right_triangle at (2, 4) with distance 1</think>

<answer>(2, 4)</answer>