There are 5 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 (3, 1)
Distance from target shape to red square at (2, 2): 2
Distance from target shape to blue right_triangle at (6, 3): 5
Distance from target shape to cyan trapezoid at (3, 8): 7
Distance from target shape to pink trapezoid at (1, 7): 8
Closest shape is the red square at (2, 2) with distance 2</think>

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