There are 4 shapes on a 8x8 grid. Which shape is closest to the red 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: red rectangle at (4, 1)
Distance from target shape to pink right_triangle at (4, 7): 6
Distance from target shape to blue rectangle at (6, 4): 5
Distance from target shape to purple trapezoid at (2, 1): 2
Closest shape is the purple trapezoid at (2, 1) with distance 2</think>

<answer>(2, 1)</answer>