So a half-life after a half-life, that makes 2 half-lives. However, they may be both left sides, therefore they dont fit together.
Left sides?
Wtf at you, let's use this logic then.
Half Life 1 is left because it's the lowest number used.
Half Life 2 is right because it's the highest number used.
Thus making a full life.
Now Episodes 1-3, I wouldn't know how to explain them.