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

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