There are 6 shapes on a 9x9 grid. Which shape is closest to the gray right_triangle in terms of Manhattan distance? The final answer is the grid position of the closest shape like (row_index, column_index).
<think>Target shape: gray right_triangle at (4, 6)
Distance from target shape to green right_triangle at (0, 4): 6
Distance from target shape to blue square at (4, 7): 1
Distance from target shape to cyan rectangle at (1, 7): 4
Distance from target shape to red trapezoid at (1, 2): 7
Distance from target shape to purple trapezoid at (0, 8): 6
Closest shape is the blue square at (4, 7) with distance 1</think>

<answer>(4, 7)</answer>