There are 5 shapes on a 8x8 grid. Which shape is closest to the purple square 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 square at (1, 6)
Distance from target shape to yellow trapezoid at (7, 3): 9
Distance from target shape to orange trapezoid at (5, 3): 7
Distance from target shape to blue trapezoid at (7, 2): 10
Distance from target shape to cyan right_triangle at (3, 5): 3
Closest shape is the cyan right_triangle at (3, 5) with distance 3</think>

<answer>(3, 5)</answer>