It is a figure that is in some respects the equivalent of the illusion of parallel lines merging on some vanishing point on the horizon like railway tracks. It is parallelism.

women of work, of leisure, of the night,
in stove-colored silks, in lace, in nothing,
with crewel needles, with books, with wide-open legs,
Lines from Eavan Boland's "The Women" collected in her selected poems 1980-1990 Outside History in which it is difficult to keep the various women separate — their lines cross and converge and again part.

And so for day 789