There are 5 shapes on a 8x8 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 (4, 0)
Distance from target shape to red square at (1, 1): 4
Distance from target shape to pink rectangle at (3, 6): 7
Distance from target shape to blue trapezoid at (6, 5): 7
Distance from target shape to brown rectangle at (7, 6): 9
Closest shape is the red square at (1, 1) with distance 4</think>

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