There are 5 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 (4, 0)
Distance from target shape to purple trapezoid at (5, 3): 4
Distance from target shape to blue trapezoid at (3, 3): 4
Distance from target shape to brown trapezoid at (6, 6): 8
Distance from target shape to yellow right_triangle at (1, 4): 7
Closest shape is the purple trapezoid at (5, 3) with distance 4</think>

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