There are 3 shapes on a 9x9 grid. Which shape is closest to the yellow rectangle in terms of Manhattan distance? The final answer is the grid position of the closest shape like (row_index, column_index).
<think>Target shape: yellow rectangle at (5, 4)
Distance from target shape to red right_triangle at (7, 3): 3
Distance from target shape to gray square at (7, 1): 5
Closest shape is the red right_triangle at (7, 3) with distance 3</think>

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