There are 4 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 (6, 0)
Distance from target shape to pink trapezoid at (1, 7): 12
Distance from target shape to cyan right_triangle at (0, 1): 7
Distance from target shape to red right_triangle at (5, 4): 5
Closest shape is the red right_triangle at (5, 4) with distance 5</think>

<answer>(5, 4)</answer>