There are 6 shapes on a 9x9 grid. Which shape is closest to the brown 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: brown square at (3, 1)
Distance from target shape to green right_triangle at (5, 7): 8
Distance from target shape to red right_triangle at (3, 6): 5
Distance from target shape to gray trapezoid at (6, 8): 10
Distance from target shape to yellow square at (8, 5): 9
Distance from target shape to blue trapezoid at (5, 8): 9
Closest shape is the red right_triangle at (3, 6) with distance 5</think>

<answer>(3, 6)</answer>