There are 6 shapes on a 7x7 grid. Which shape is closest to the green 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: green right_triangle at (5, 5)
Distance from target shape to purple right_triangle at (1, 6): 5
Distance from target shape to cyan rectangle at (3, 4): 3
Distance from target shape to gray right_triangle at (2, 3): 5
Distance from target shape to blue square at (1, 5): 4
Distance from target shape to red trapezoid at (3, 6): 3
Closest shape is the cyan rectangle at (3, 4) with distance 3</think>

<answer>(3, 4)</answer>