No cable of any kind is directional unless it is made with some electrical component (like a diode) in-line between the amp and speaker. If you (generally) believe electricity can recognize one cable from another, you don't understand electricity.
Furutech Nanoflux speaker cables
Are Furutech Nanoflux speaker cables directional? If they are how do you know which is the amp end and which is the speaker end? I only found one article at Positive Feedback that said the noise filter should be closer to the source but I haven't been able to find any information that would confirm that and the person who lent me his cables swears it goes the other way. I have listened, and do hear a real difference but it is unclear to me which is "better".