There are 3 shapes on a 10x10 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 (7, 3)
Distance from target shape to blue right_triangle at (1, 1): 8
Distance from target shape to green rectangle at (6, 1): 3
Closest shape is the green rectangle at (6, 1) with distance 3</think>

<answer>(6, 1)</answer>