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 (7, 4)
Distance from target shape to cyan right_triangle at (3, 6): 6
Distance from target shape to blue square at (6, 0): 5
Distance from target shape to purple rectangle at (8, 3): 2
Distance from target shape to orange square at (0, 8): 11
Distance from target shape to red rectangle at (8, 6): 3
Closest shape is the purple rectangle at (8, 3) with distance 2</think>

<answer>(8, 3)</answer>