There are 3 shapes on a 8x8 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 (3, 0)
Distance from target shape to blue right_triangle at (5, 4): 6
Distance from target shape to red rectangle at (5, 0): 2
Closest shape is the red rectangle at (5, 0) with distance 2</think>

<answer>(5, 0)</answer>