There are 5 shapes on a 6x6 grid. Which shape is closest to the orange 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: orange right_triangle at (3, 1)
Distance from target shape to yellow rectangle at (2, 2): 2
Distance from target shape to pink right_triangle at (2, 1): 1
Distance from target shape to green rectangle at (0, 5): 7
Distance from target shape to gray trapezoid at (1, 4): 5
Closest shape is the pink right_triangle at (2, 1) with distance 1</think>

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