There are 6 shapes on a 10x10 grid. Which shape is closest to the cyan 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: cyan right_triangle at (1, 5)
Distance from target shape to blue rectangle at (7, 4): 7
Distance from target shape to brown square at (7, 8): 9
Distance from target shape to orange right_triangle at (3, 0): 7
Distance from target shape to red rectangle at (1, 3): 2
Distance from target shape to gray square at (3, 1): 6
Closest shape is the red rectangle at (1, 3) with distance 2</think>

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