Mirrors, portals. [Mariusz Lewandowski]
Time Portal by artist Thomas Stoop.
How to Create Realistic Portal Art in Photoshop Tutorial
Madame la Science Art Print by Xfreischutz
portal 2 In the end by ~biggreenpepper on deviantART
Portal, GLaDOS, Chelle, Video Game, Artwork, Fan Art Portal Cake by ChasingArtwork
GG Valve... #Portal via Reddit user AntneyW
Art Nouveau Chell Poster! I have no idea who first came up with the idea for nerdy Art Nouveau, but I love it. Whoever you are, I owe you a drink!
The Cwafty Blog: Tutorial Tuesday/Monday: Portal Lemon-ade Wall Display
[Riot Art Contest] Darin Walsh - Polycount Forum