There are 4 shapes on a 7x7 grid. Which shape is closest to the brown right_triangle in terms of Manhattan distance? The final answer is the grid position of the closest shape like (row_index, column_index).
<think>Target shape: brown right_triangle at (0, 3)
Distance from target shape to cyan right_triangle at (1, 5): 3
Distance from target shape to yellow right_triangle at (1, 0): 4
Distance from target shape to purple square at (6, 3): 6
Closest shape is the cyan right_triangle at (1, 5) with distance 3</think>

<answer>(1, 5)</answer>