There are 3 shapes on a 9x9 grid. Which shape is closest to the red 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: red right_triangle at (6, 4)
Distance from target shape to green square at (0, 8): 10
Distance from target shape to cyan rectangle at (8, 3): 3
Closest shape is the cyan rectangle at (8, 3) with distance 3</think>

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