There are 3 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 (7, 5)
Distance from target shape to cyan square at (1, 4): 7
Distance from target shape to blue rectangle at (1, 6): 7
Closest shape is the cyan square at (1, 4) with distance 7</think>

<answer>(1, 4)</answer>