There are 6 shapes on a 9x9 grid. Which shape is closest to the blue 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: blue trapezoid at (7, 1)
Distance from target shape to orange right_triangle at (4, 1): 3
Distance from target shape to gray rectangle at (7, 3): 2
Distance from target shape to purple rectangle at (3, 1): 4
Distance from target shape to red square at (4, 0): 4
Distance from target shape to brown trapezoid at (1, 2): 7
Closest shape is the gray rectangle at (7, 3) with distance 2</think>

<answer>(7, 3)</answer>