There are 5 shapes on a 10x10 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 (3, 4)
Distance from target shape to pink square at (5, 2): 4
Distance from target shape to blue square at (1, 5): 3
Distance from target shape to gray square at (8, 7): 8
Distance from target shape to yellow right_triangle at (2, 7): 4
Closest shape is the blue square at (1, 5) with distance 3</think>

<answer>(1, 5)</answer>