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 (3, 2)
Distance from target shape to brown square at (3, 3): 1
Distance from target shape to cyan square at (0, 2): 3
Distance from target shape to purple right_triangle at (1, 1): 3
Distance from target shape to gray trapezoid at (0, 0): 5
Closest shape is the brown square at (3, 3) with distance 1</think>

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