There are 6 shapes on a 10x10 grid. Which shape is closest to the red 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: red right_triangle at (4, 8)
Distance from target shape to gray trapezoid at (3, 0): 9
Distance from target shape to green trapezoid at (6, 0): 10
Distance from target shape to blue right_triangle at (6, 1): 9
Distance from target shape to pink right_triangle at (4, 2): 6
Distance from target shape to brown right_triangle at (5, 8): 1
Closest shape is the brown right_triangle at (5, 8) with distance 1</think>

<answer>(5, 8)</answer>