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

<answer>(4, 6)</answer>