There are 5 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 (4, 2)
Distance from target shape to orange trapezoid at (4, 6): 4
Distance from target shape to cyan right_triangle at (2, 1): 3
Distance from target shape to purple trapezoid at (5, 4): 3
Distance from target shape to red right_triangle at (6, 3): 3
Closest shape is the cyan right_triangle at (2, 1) with distance 3</think>

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