There are 6 shapes on a 8x8 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 (0, 6)
Distance from target shape to brown right_triangle at (1, 2): 5
Distance from target shape to blue rectangle at (7, 1): 12
Distance from target shape to red right_triangle at (1, 1): 6
Distance from target shape to purple trapezoid at (7, 2): 11
Distance from target shape to orange right_triangle at (4, 0): 10
Closest shape is the brown right_triangle at (1, 2) with distance 5</think>

<answer>(1, 2)</answer>