They condense from the vapor, get jiggled and jostled, coalesce, and then suddenly, they freeze.

You can see a few strands, more nearly vertical, that must have had a drop slide down soon before freezing, sweeping out all the other droplets and leaving only a thread of densely packed tiny drops.

The freezing, one started, likely spreads along a thin film on the web from drop to drop, freezing all drops. The largest drops tend to be at thread intersections that tended to keep them from moving further. Other droplets may have slid along, only to collide and coalesce with the one fixed to several threads.

The spider made mostly four-sided polygons, though in the center of the web, you find more variety. Some triangles, some pentagonal, some hexagonal.

In the atmosphere, we call just-frozen droplets, having only enough vapor growth to imagine facets, as droxtals. Perhaps some of the smallest ones here could be droxtals.

--JN