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

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