There are 5 shapes on a 4x4 grid. Which shape is closest to the purple 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: purple right_triangle at (3, 2)
Distance from target shape to cyan rectangle at (2, 3): 2
Distance from target shape to blue trapezoid at (3, 1): 1
Distance from target shape to yellow rectangle at (1, 2): 2
Distance from target shape to gray square at (2, 2): 1
Closest shape is the blue trapezoid at (3, 1) with distance 1</think>

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