There are 5 shapes on a 8x8 grid. Which shape is closest to the green 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: green right_triangle at (4, 1)
Distance from target shape to cyan square at (5, 2): 2
Distance from target shape to gray right_triangle at (2, 1): 2
Distance from target shape to brown right_triangle at (4, 4): 3
Distance from target shape to red trapezoid at (7, 6): 8
Closest shape is the cyan square at (5, 2) with distance 2</think>

<answer>(5, 2)</answer>