There are 4 shapes on a 8x8 grid. Which shape is closest to the orange 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: orange right_triangle at (4, 1)
Distance from target shape to cyan right_triangle at (5, 4): 4
Distance from target shape to pink rectangle at (3, 6): 6
Distance from target shape to brown trapezoid at (0, 4): 7
Closest shape is the cyan right_triangle at (5, 4) with distance 4</think>

<answer>(5, 4)</answer>