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

<answer>(0, 1)</answer>