There are 6 shapes on a 6x6 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 (5, 1)
Distance from target shape to orange trapezoid at (0, 4): 8
Distance from target shape to brown rectangle at (3, 4): 5
Distance from target shape to pink square at (4, 3): 3
Distance from target shape to cyan right_triangle at (0, 2): 6
Distance from target shape to blue square at (2, 5): 7
Closest shape is the pink square at (4, 3) with distance 3</think>

<answer>(4, 3)</answer>