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

<answer>(7, 3)</answer>