There are 6 shapes on a 8x8 grid. Which shape is closest to the yellow 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: yellow right_triangle at (3, 7)
Distance from target shape to cyan rectangle at (4, 7): 1
Distance from target shape to pink right_triangle at (4, 6): 2
Distance from target shape to red rectangle at (7, 6): 5
Distance from target shape to green square at (1, 6): 3
Distance from target shape to brown right_triangle at (2, 5): 3
Closest shape is the cyan rectangle at (4, 7) with distance 1</think>

<answer>(4, 7)</answer>