There are 6 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 (2, 3)
Distance from target shape to orange rectangle at (3, 1): 3
Distance from target shape to brown square at (3, 2): 2
Distance from target shape to purple trapezoid at (2, 1): 2
Distance from target shape to yellow rectangle at (0, 1): 4
Distance from target shape to pink square at (1, 3): 1
Closest shape is the pink square at (1, 3) with distance 1</think>

<answer>(1, 3)</answer>