Meanings of crisscross beams in English

Overhead are thick, crisscrossing beams, darkened by years of woodsmoke from the fireplace.

Beyond it was only empty space, punctuated by the crisscrossing beams of a dozen spotlights.

Crisscrossing beams of lasers form a crystal-like structure that defines the boundaries of each atom's confined space, like the contoured cardboard of an egg carton.