There are 4 shapes on a 5x5 grid. Which shape is closest to the gray 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: gray right_triangle at (0, 4)
Distance from target shape to red rectangle at (3, 1): 6
Distance from target shape to brown square at (4, 2): 6
Distance from target shape to yellow rectangle at (2, 1): 5
Closest shape is the yellow rectangle at (2, 1) with distance 5</think>

<answer>(2, 1)</answer>