ahah well first i must ask you, are they called Twicks where you live? or are you making a singular noun out of a possible plural noun Twix? lol
i always refer to both the collective and the individual units as Twix
and then really how do you determine which is on the left or the right. those are relative terms.
but, i am checking with Little Roomba for you---
she also does not know the difference between left or right. i think this might be why she gets stuck underneath my bed all the time to be honest.
Yes, i call them a Twick when it is one and Twix when they are in a pair. hahaha