There are 4 shapes on a 7x7 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 (0, 3)
Distance from target shape to pink rectangle at (6, 0): 9
Distance from target shape to brown rectangle at (4, 0): 7
Distance from target shape to yellow right_triangle at (4, 3): 4
Closest shape is the yellow right_triangle at (4, 3) with distance 4</think>

<answer>(4, 3)</answer>