As mentioned some writings ago, the essence of the highest form of the visual arts - arts in general, really - is that of the use of metaphoric relationships... this can also be utilized as the metaphor itself as analogy for the human - especially in terms of still lifes... in such manner, the attributes of being human can be explored and built on, to the extent of being able to include this metaphoring within works which actually display concrete examplings of humans, thus utilizing the within still life metaphor as a turn point in which to be able to attribute the same to the humans displayed.... consequently then, aggregates can be shown without the work and not have confusion of them as being tribal in nature - provided, of course, the within still life is consistant with the proscribed theme/titling wherein are shown the concretes of humans... in the still lifes, diversity can be noted via use of obviously different species [as seen, for instance, in "Critical Mass" - which while may not be nominally considered as still life, yet is 'stilled life' and so fits in]...