There are 6 shapes on a 9x9 grid. Which shape is closest to the green 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: green rectangle at (0, 0)
Distance from target shape to red rectangle at (1, 5): 6
Distance from target shape to gray square at (6, 7): 13
Distance from target shape to cyan trapezoid at (4, 5): 9
Distance from target shape to blue rectangle at (6, 6): 12
Distance from target shape to purple right_triangle at (6, 3): 9
Closest shape is the red rectangle at (1, 5) with distance 6</think>

<answer>(1, 5)</answer>