There are 4 shapes on a 7x7 grid. Which shape is closest to the brown 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: brown rectangle at (4, 6)
Distance from target shape to purple right_triangle at (6, 5): 3
Distance from target shape to cyan square at (3, 0): 7
Distance from target shape to red rectangle at (6, 0): 8
Closest shape is the purple right_triangle at (6, 5) with distance 3</think>

<answer>(6, 5)</answer>