The poem imagines light as something being born, struggling its way into awareness. At first it is frantic: "desperate thrashing," springing "out of nothing," then "out of nowhere." The repeated stanza, with only a small change in wording, feels like a second attempt, as if the birth can't quite get going on the first try. The odd "#o" in the opening and the strange word "plodes" look like glitches or stumbles, which suits the awkward effort the poem describes.
Then the movement changes. Light "plows the void" and leaves "veins of blood-radiance," a striking image that makes it feel bodily and alive. It "catches its stride," gains confidence, and finally comes to know the emptiness around it "as its own / flower bed." What once seemed hostile becomes a place to grow.
The mood moves from panic and struggle to calm, quiet triumph. The short last line, "light blooms," feels like a deep breath let out.