There are 4 shapes on a 7x7 grid. Which shape is closest to the gray 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: gray square at (1, 6)
Distance from target shape to green right_triangle at (4, 4): 5
Distance from target shape to purple rectangle at (3, 1): 7
Distance from target shape to orange trapezoid at (1, 1): 5
Closest shape is the green right_triangle at (4, 4) with distance 5</think>

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