There are 6 shapes on a 10x10 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 (8, 3)
Distance from target shape to cyan rectangle at (0, 5): 10
Distance from target shape to green square at (0, 6): 11
Distance from target shape to red right_triangle at (7, 3): 1
Distance from target shape to brown square at (3, 1): 7
Distance from target shape to gray right_triangle at (9, 0): 4
Closest shape is the red right_triangle at (7, 3) with distance 1</think>

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