There are 5 shapes on a 4x4 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 (0, 3)
Distance from target shape to pink square at (2, 3): 2
Distance from target shape to orange trapezoid at (1, 1): 3
Distance from target shape to blue right_triangle at (3, 2): 4
Distance from target shape to cyan rectangle at (2, 1): 4
Closest shape is the pink square at (2, 3) with distance 2</think>

<answer>(2, 3)</answer>