There are 4 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 (5, 1)
Distance from target shape to purple rectangle at (0, 1): 5
Distance from target shape to cyan rectangle at (1, 5): 8
Distance from target shape to gray square at (2, 3): 5
Closest shape is the purple rectangle at (0, 1) with distance 5</think>

<answer>(0, 1)</answer>