There are 6 shapes on a 4x4 grid. Which shape is closest to the purple rectangle 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 rectangle at (3, 3)
Distance from target shape to yellow rectangle at (0, 2): 4
Distance from target shape to blue square at (2, 3): 1
Distance from target shape to orange rectangle at (0, 0): 6
Distance from target shape to cyan right_triangle at (1, 0): 5
Distance from target shape to gray trapezoid at (3, 0): 3
Closest shape is the blue square at (2, 3) with distance 1</think>

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