There are 6 shapes on a 6x6 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 (3, 5)
Distance from target shape to gray rectangle at (3, 2): 3
Distance from target shape to purple right_triangle at (3, 3): 2
Distance from target shape to pink trapezoid at (5, 0): 7
Distance from target shape to cyan right_triangle at (1, 3): 4
Distance from target shape to brown rectangle at (2, 1): 5
Closest shape is the purple right_triangle at (3, 3) with distance 2</think>

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