Photo and texture credits — all free to use under the Unsplash License (https://unsplash.com/license),
video under the Pexels License (https://www.pexels.com/license/). Every image carries Portal's grade.

dark-sea ........... Michael Benz (Unsplash)
pine-ink ........... Dmitry Romanoff (Unsplash), inked by Portal
night-silk ......... Portal (our liquid light, softened into night)
hammered-glass ..... A. C. (Unsplash)
video/dark-shore ... Pexels video 14046798 (Pexels License)
liquid-light ....... Portal (a still of our own liquid light)
glass/forest-lake .. Solomon Arvin (his own photograph)
glass/pine-hills ... Rowan Heuvel (Unsplash)
glass/sunrise-lake . Scott Goodwill (Unsplash)
shots/ ............. screenshots of Portal's own concept sites