There are 3 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 (2, 3)
Distance from target shape to gray trapezoid at (3, 1): 3
Distance from target shape to blue square at (3, 0): 4
Closest shape is the gray trapezoid at (3, 1) with distance 3</think>

<answer>(3, 1)</answer>