There are 5 shapes on a 4x4 grid. Which shape is closest to the yellow 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: yellow square at (2, 1)
Distance from target shape to blue right_triangle at (1, 1): 1
Distance from target shape to purple right_triangle at (2, 3): 2
Distance from target shape to cyan trapezoid at (0, 0): 3
Distance from target shape to brown right_triangle at (3, 3): 3
Closest shape is the blue right_triangle at (1, 1) with distance 1</think>

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