There are 4 shapes on a 7x7 grid. Which shape is closest to the red trapezoid in terms of Manhattan distance? The final answer is the grid position of the closest shape like (row_index, column_index).
<think>Target shape: red trapezoid at (1, 5)
Distance from target shape to green right_triangle at (0, 3): 3
Distance from target shape to blue rectangle at (3, 6): 3
Distance from target shape to yellow right_triangle at (6, 3): 7
Closest shape is the green right_triangle at (0, 3) with distance 3</think>

<answer>(0, 3)</answer>