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

<answer>(6, 1)</answer>