Densen

I see a singing darkness in my unseeing eyes. Of neither water, nor earth, nor night. It quivers, densens, then explodes in black. Then it falls away in strings of rippling beads. And again it quivers, densens. Can you hear it?

Source: wiktionary

Traffic densens as the morning ticks on. Trucks roar past on the nearside lane, but I'm well protected by a decent width of shoulder.

Source: wiktionary

Sit in a chair looking south into blue twilight that arrives earlier every day— as the sky flakes and densens, as the first clear flakes float past the porch's wood to light on dirt of the driveway and on brown frozen grass or dry stalks of the flower border.

Source: wiktionary