There are 4 shapes on a 6x6 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 (5, 5)
Distance from target shape to blue square at (2, 0): 8
Distance from target shape to brown square at (0, 3): 7
Distance from target shape to red right_triangle at (1, 2): 7
Closest shape is the brown square at (0, 3) with distance 7</think>

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