There are 5 shapes on a 8x8 grid. Which shape is closest to the green rectangle 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 rectangle at (3, 6)
Distance from target shape to pink right_triangle at (1, 4): 4
Distance from target shape to gray trapezoid at (7, 0): 10
Distance from target shape to yellow right_triangle at (5, 1): 7
Distance from target shape to cyan rectangle at (4, 3): 4
Closest shape is the pink right_triangle at (1, 4) with distance 4</think>

<answer>(1, 4)</answer>