There are 4 shapes on a 6x6 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 (3, 2)
Distance from target shape to gray square at (4, 4): 3
Distance from target shape to green rectangle at (4, 1): 2
Distance from target shape to purple trapezoid at (0, 0): 5
Closest shape is the green rectangle at (4, 1) with distance 2</think>

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