It needs horizontal dividing lines to show that the bodies are presented in pairs at the same scale.
When you first look at it, it seems like all six are in one picture at the same scale, then you start noticing things appearing twice, and think "hang on that's not right" and work it out, but just two lines would have solved it immediately.
The point of good presentation and design cues is that they can make information instantly clear to almost everyone, no matter if their brain is the size of TON 618, or not.