There are 5 shapes on a 7x7 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, 3)
Distance from target shape to yellow square at (4, 5): 6
Distance from target shape to red trapezoid at (4, 6): 7
Distance from target shape to brown rectangle at (5, 6): 8
Distance from target shape to purple trapezoid at (3, 1): 5
Closest shape is the purple trapezoid at (3, 1) with distance 5</think>

<answer>(3, 1)</answer>