There are 5 shapes on a 8x8 grid. Which shape is closest to the green square 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 square at (6, 4)
Distance from target shape to cyan right_triangle at (5, 0): 5
Distance from target shape to gray right_triangle at (4, 0): 6
Distance from target shape to orange rectangle at (3, 2): 5
Distance from target shape to blue square at (1, 1): 8
Closest shape is the cyan right_triangle at (5, 0) with distance 5</think>

<answer>(5, 0)</answer>