There are 6 shapes on a 7x7 grid. Which shape is closest to the purple 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: purple right_triangle at (0, 3)
Distance from target shape to green right_triangle at (5, 2): 6
Distance from target shape to red rectangle at (3, 5): 5
Distance from target shape to cyan right_triangle at (5, 4): 6
Distance from target shape to brown right_triangle at (6, 1): 8
Distance from target shape to blue trapezoid at (2, 6): 5
Closest shape is the red rectangle at (3, 5) with distance 5</think>

<answer>(3, 5)</answer>