There are 3 shapes on a 7x7 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 (1, 6)
Distance from target shape to orange right_triangle at (3, 6): 2
Distance from target shape to yellow right_triangle at (1, 0): 6
Closest shape is the orange right_triangle at (3, 6) with distance 2</think>

<answer>(3, 6)</answer>