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 (4, 0)
Distance from target shape to gray right_triangle at (0, 5): 9
Distance from target shape to orange square at (7, 1): 4
Distance from target shape to green trapezoid at (1, 7): 10
Distance from target shape to cyan trapezoid at (3, 1): 2
Distance from target shape to brown right_triangle at (2, 6): 8
Closest shape is the cyan trapezoid at (3, 1) with distance 2</think>

<answer>(3, 1)</answer>