f77v top nymphs

[MarcoP]

I'll just throw this in as an additional possibility about this image:
I find this illustration has parallels in the study on the Livre d'Ethiques I linked to in my post about poses, which you can read You are not allowed to view links. Register or Login to view. .
Specifically I see a parallel between the structure of this image and that of the iconography depicted in figures 12A & 14:
At the center there is Virtue with her arms extended to both sides. On either side are the Vices: Excess and Default. Closer to her are the personifications of Good Will and Knowledge.
In the Voynich there are five labels also. It could be interpreted as Virtue in the Center, Default on the left, Excess on the right (note that the left nymph stands in a rather simple tub compared to the right nymph, which stands in a more ornate one).
Immediately to the left and right of the central figure there are two labelled tube ends: these could be Good Will and Knowledge.

I think Vviews is right in considering the symmetric structure of the composition relevant.

• The fact that Christ Pantocrator has a pose similar to that of the central nymph has been mentioned above. You are not allowed to view links. Register or Login to view. contains the Commentary on the Apocalypse by  Beatus of Liébana. There are several illustrations that can be compared with the central nymph and in a few cases the figure of Christ at the centre is accompanied by two symmetrical figures (angels, in this example, together with two symmetrical groups of three haloed saints? each).
  
• Liber ad honorem Augusti is a work by Petrus of Eboli (the author of You are not allowed to view links. Register or Login to view.). This illustration represents emperor Fredrick I and his sons Henry and Philip. This parallel is particularly close to the VMS illustration because it only includes three people.
  
• The Lorenzetti fresco in Siena is a moral allegory (as the examples discussed by Vviews). In this case, the symmetrical groups are more complex, each including an angel and two men.
  
• The black and white illustration is one of the images mentioned by VViews (12a).
  
  

These parallels could help us understand more of the meaning of the You are not allowed to view links. Register or Login to view. illustration. The sitting figure at the centre seems to always be more “important” than the two figures (or groups) at the sides. His/her open arms seem to project some kind of “power” or “protection” on the figures at the sides.
The “pipes”, “tubs” and “fluids” remain substantially unparalleled by these examples. The Beatus illustration at least includes prominent non-human features: the circular frame around Christ, the two large discs (Sun and Moon) at the bottom. The Voynich "pipes" are quite different and clearly deserve a deeper investigation. Moreover, it seems that in the VMS the labels apply to the pipes rather than to the nymphs. This is of course a major difference from the other examples: in the other cases, labels apply to the human figures.