There are 6 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 (5, 2)
Distance from target shape to brown square at (5, 5): 3
Distance from target shape to cyan rectangle at (4, 5): 4
Distance from target shape to green trapezoid at (2, 4): 5
Distance from target shape to blue right_triangle at (6, 3): 2
Distance from target shape to yellow right_triangle at (4, 6): 5
Closest shape is the blue right_triangle at (6, 3) with distance 2</think>

<answer>(6, 3)</answer>