There are 5 shapes on a 5x5 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, 1)
Distance from target shape to brown trapezoid at (2, 3): 3
Distance from target shape to yellow right_triangle at (2, 2): 2
Distance from target shape to cyan trapezoid at (4, 2): 4
Distance from target shape to blue trapezoid at (2, 1): 1
Closest shape is the blue trapezoid at (2, 1) with distance 1</think>

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