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

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