Heroes ten and eleven are the first superteam in the Fifty Superheroes Universe. (Which is apparently a thing.) The Venn Siblings are pretty clearly in the “Wonder Twin” class: a pair of sibs whose individual powers combine to create effects that are more than the sum of their parts. Some Wonder Twins may not even have powers of their own, but I think the Venns’ cloaks are pretty clearly individual Special Items or Gadgets– ones that probably provide and control some kind of abilities related to concealment or stealth.
Note that the Venns aren’t necessarily twins, and their genders aren’t specified. They are drawn to the same model, which represents a strong family resemblance, but with slight differences in size and build. This may mean that one is a guy and the other a gal, but it could just as easily be a simple matter of random variation. Maybe they preserve a sense of this mystery with their fictional acquaintances as well as the readers?
Artistically, the Venns are, frankly, a real pain in the neck to draw with actual pens. A close look at this drawing will reveal some pretty crudely managed corrections, and the problems with repeating their cloaks over and over again in continuity are easy to imagine. These characters would shine, however, in comics created in a combination of natural and digital media, where the empty spaces with their brushwork boundaries can be easily filled with automated colors or patterns.
The combined area of their cloaks (of course) represents the intersection of the set “Kinds of Diagrams” and the set “Things That are Named After the Person Who Invented Them”.