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

<answer>(1, 4)</answer>