There are 6 shapes on a 7x7 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, 1)
Distance from target shape to pink right_triangle at (3, 6): 7
Distance from target shape to brown square at (4, 2): 2
Distance from target shape to cyan trapezoid at (3, 2): 3
Distance from target shape to blue square at (4, 4): 4
Distance from target shape to gray square at (4, 0): 2
Closest shape is the brown square at (4, 2) with distance 2</think>

<answer>(4, 2)</answer>