Gnot Even 
[@Smithers](/images/3042925#comment_10406695)
> If I could upvote a comment for correct usage of quarter-wind compass points, I would.
Can't everyone box the compass?
[@Stellarator](/images/3042925#comment_10406643)
> I wasn't able to make the suggested layout work in a way that looked good, but using that as a starting point, I think I've made it more readable. (hope I didn't miss anypony)
That seems about as clear as possible. I wonder if adding a different sort of line (dot-dot-dot or dot-dash-dot or somesuch) to show family relationships would be useful. So the three sirens have a family connection, as do Smoothie and Juice, and also the three princesses. Might explain why they don't have sex with each other - or, on the otherhand, might just clutter the diagram.
(I note Rarity is strategically positioned...)
> If I could upvote a comment for correct usage of quarter-wind compass points, I would.
Can't everyone box the compass?
[@Stellarator](/images/3042925#comment_10406643)
> I wasn't able to make the suggested layout work in a way that looked good, but using that as a starting point, I think I've made it more readable. (hope I didn't miss anypony)
That seems about as clear as possible. I wonder if adding a different sort of line (dot-dot-dot or dot-dash-dot or somesuch) to show family relationships would be useful. So the three sirens have a family connection, as do Smoothie and Juice, and also the three princesses. Might explain why they don't have sex with each other - or, on the otherhand, might just clutter the diagram.
(I note Rarity is strategically positioned...)