There are 4 shapes on a 10x10 grid. Which shape is closest to the green 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: green square at (5, 5)
Distance from target shape to cyan trapezoid at (0, 4): 6
Distance from target shape to pink square at (7, 7): 4
Distance from target shape to purple right_triangle at (5, 8): 3
Closest shape is the purple right_triangle at (5, 8) with distance 3</think>

<answer>(5, 8)</answer>