Ex. Ashley and Steve are a couple. (To represent we will use the variables, A for Ashley and S for Steve). Emily decides to come and switch places with Ashley. (E is for Emily)
----- AS + E--->> ES + A, this is the Generic equation
Ashley and Steve were a compound but Emily is an element so she went and switched places with Ashley thus making her and Steve a compound and Ashley, an element.

Analogy to Everyday Life