There are 3 shapes on a 8x8 grid. Which shape is closest to the gray 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: gray right_triangle at (4, 7)
Distance from target shape to purple rectangle at (1, 0): 10
Distance from target shape to blue square at (6, 2): 7
Closest shape is the blue square at (6, 2) with distance 7</think>

<answer>(6, 2)</answer>