There are 4 shapes on a 10x10 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 (5, 8)
Distance from target shape to pink right_triangle at (5, 3): 5
Distance from target shape to red right_triangle at (8, 7): 4
Distance from target shape to cyan right_triangle at (5, 6): 2
Closest shape is the cyan right_triangle at (5, 6) with distance 2</think>

<answer>(5, 6)</answer>