There are 4 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 (5, 3)
Distance from target shape to yellow trapezoid at (1, 5): 6
Distance from target shape to gray right_triangle at (0, 3): 5
Distance from target shape to brown square at (4, 4): 2
Closest shape is the brown square at (4, 4) with distance 2</think>

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