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 (9, 8)
Distance from target shape to blue trapezoid at (3, 5): 9
Distance from target shape to yellow trapezoid at (1, 2): 14
Distance from target shape to cyan square at (8, 1): 8
Distance from target shape to gray rectangle at (7, 2): 8
Closest shape is the cyan square at (8, 1) with distance 8</think>

<answer>(8, 1)</answer>