There are 6 shapes on a 7x7 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 (5, 2)
Distance from target shape to purple rectangle at (1, 6): 8
Distance from target shape to gray square at (4, 0): 3
Distance from target shape to orange square at (1, 3): 5
Distance from target shape to green right_triangle at (3, 6): 6
Distance from target shape to pink square at (2, 5): 6
Closest shape is the gray square at (4, 0) with distance 3</think>

<answer>(4, 0)</answer>