There are 2 shapes on a 6x6 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 (1, 5)
Distance from target shape to green rectangle at (5, 5): 4
Closest shape is the green rectangle at (5, 5) with distance 4</think>

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