There are 6 shapes on a 8x8 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 (1, 2)
Distance from target shape to blue square at (6, 2): 5
Distance from target shape to gray trapezoid at (1, 3): 1
Distance from target shape to red right_triangle at (7, 4): 8
Distance from target shape to orange right_triangle at (7, 7): 11
Distance from target shape to green right_triangle at (5, 3): 5
Closest shape is the gray trapezoid at (1, 3) with distance 1</think>

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