There are 3 shapes on a 7x7 grid. Which shape is closest to the blue 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: blue square at (1, 3)
Distance from target shape to green square at (0, 1): 3
Distance from target shape to red trapezoid at (4, 4): 4
Closest shape is the green square at (0, 1) with distance 3</think>

<answer>(0, 1)</answer>