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

<answer>(1, 3)</answer>