There are 6 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, 4)
Distance from target shape to blue rectangle at (0, 0): 10
Distance from target shape to pink trapezoid at (3, 0): 7
Distance from target shape to yellow right_triangle at (4, 2): 4
Distance from target shape to brown square at (5, 0): 5
Distance from target shape to green rectangle at (1, 2): 7
Closest shape is the yellow right_triangle at (4, 2) with distance 4</think>

<answer>(4, 2)</answer>