There are 5 shapes on a 10x10 grid. Which shape is closest to the blue 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: blue right_triangle at (3, 9)
Distance from target shape to cyan right_triangle at (9, 2): 13
Distance from target shape to gray right_triangle at (1, 0): 11
Distance from target shape to purple rectangle at (2, 8): 2
Distance from target shape to green rectangle at (8, 2): 12
Closest shape is the purple rectangle at (2, 8) with distance 2</think>

<answer>(2, 8)</answer>