There are 4 shapes on a 8x8 grid. Which shape is closest to the green 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: green right_triangle at (3, 0)
Distance from target shape to orange right_triangle at (0, 3): 6
Distance from target shape to purple square at (4, 5): 6
Distance from target shape to brown trapezoid at (6, 3): 6
Closest shape is the orange right_triangle at (0, 3) with distance 6</think>

<answer>(0, 3)</answer>