There are 4 shapes on a 7x7 grid. Which shape is closest to the blue 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: blue right_triangle at (5, 5)
Distance from target shape to cyan square at (1, 3): 6
Distance from target shape to gray rectangle at (0, 4): 6
Distance from target shape to yellow right_triangle at (4, 1): 5
Closest shape is the yellow right_triangle at (4, 1) with distance 5</think>

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