There are 6 shapes on a 8x8 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 (4, 3)
Distance from target shape to red square at (3, 3): 1
Distance from target shape to cyan right_triangle at (7, 5): 5
Distance from target shape to green trapezoid at (3, 6): 4
Distance from target shape to gray right_triangle at (0, 2): 5
Distance from target shape to purple rectangle at (2, 6): 5
Closest shape is the red square at (3, 3) with distance 1</think>

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