There are 6 shapes on a 10x10 grid. Which shape is closest to the blue square in terms of Manhattan distance? The final answer is the grid position of the closest shape like (row_index, column_index).
<think>Target shape: blue square at (2, 1)
Distance from target shape to purple rectangle at (1, 3): 3
Distance from target shape to green trapezoid at (9, 9): 15
Distance from target shape to cyan trapezoid at (8, 3): 8
Distance from target shape to brown square at (5, 8): 10
Distance from target shape to gray right_triangle at (9, 7): 13
Closest shape is the purple rectangle at (1, 3) with distance 3</think>

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