There are 4 shapes on a 8x8 grid. Which shape is closest to the blue 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: blue rectangle at (1, 6)
Distance from target shape to brown rectangle at (4, 5): 4
Distance from target shape to red square at (6, 3): 8
Distance from target shape to pink right_triangle at (1, 7): 1
Closest shape is the pink right_triangle at (1, 7) with distance 1</think>

<answer>(1, 7)</answer>