There are 5 shapes on a 7x7 grid. Which shape is closest to the gray 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: gray square at (6, 6)
Distance from target shape to red square at (5, 4): 3
Distance from target shape to cyan right_triangle at (3, 4): 5
Distance from target shape to blue right_triangle at (1, 1): 10
Distance from target shape to pink square at (3, 0): 9
Closest shape is the red square at (5, 4) with distance 3</think>

<answer>(5, 4)</answer>