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

<answer>(3, 4)</answer>