There are 4 shapes on a 6x6 grid. Which shape is closest to the purple 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: purple right_triangle at (0, 4)
Distance from target shape to yellow square at (4, 1): 7
Distance from target shape to orange right_triangle at (4, 0): 8
Distance from target shape to red right_triangle at (5, 2): 7
Closest shape is the yellow square at (4, 1) with distance 7</think>

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