There are 6 shapes on a 6x6 grid. Which shape is closest to the purple square 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 square at (5, 1)
Distance from target shape to yellow square at (3, 0): 3
Distance from target shape to red right_triangle at (2, 3): 5
Distance from target shape to gray right_triangle at (3, 4): 5
Distance from target shape to brown trapezoid at (1, 3): 6
Distance from target shape to cyan trapezoid at (2, 0): 4
Closest shape is the yellow square at (3, 0) with distance 3</think>

<answer>(3, 0)</answer>