There are 5 shapes on a 7x7 grid. Which shape is closest to the red square 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 square at (1, 1)
Distance from target shape to blue trapezoid at (4, 3): 5
Distance from target shape to green right_triangle at (1, 5): 4
Distance from target shape to orange rectangle at (6, 6): 10
Distance from target shape to brown right_triangle at (4, 4): 6
Closest shape is the green right_triangle at (1, 5) with distance 4</think>

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