There are 5 shapes on a 6x6 grid. Which shape is closest to the blue 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: blue right_triangle at (2, 4)
Distance from target shape to yellow trapezoid at (5, 1): 6
Distance from target shape to brown square at (4, 2): 4
Distance from target shape to green right_triangle at (5, 4): 3
Distance from target shape to gray rectangle at (2, 3): 1
Closest shape is the gray rectangle at (2, 3) with distance 1</think>

<answer>(2, 3)</answer>