相交de线不平行平行de线不相交
[xiāng jiāo de xiàn bù píng xíng píng xíng de xiàn bù xiāng jiāo]
'Lines that intersect cannot be parallel; lines that are parallel will not intersect'. Using geometry as metaphor, it conveys the idea of two different paths or destinies - one where they cross paths only once, then diverge forever, and another where their paths run along each other but never actually meet.