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

<answer>(4, 7)</answer>