There are 3 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 (5, 3)
Distance from target shape to gray rectangle at (8, 3): 3
Distance from target shape to blue trapezoid at (9, 3): 4
Closest shape is the gray rectangle at (8, 3) with distance 3</think>

<answer>(8, 3)</answer>