There are 3 shapes on a 8x8 grid. Which shape is closest to the red 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: red right_triangle at (4, 3)
Distance from target shape to orange rectangle at (5, 5): 3
Distance from target shape to cyan right_triangle at (4, 1): 2
Closest shape is the cyan right_triangle at (4, 1) with distance 2</think>

<answer>(4, 1)</answer>