Aperture Science logo with robot

1680 × 1050

Portal turret scene

1920 × 1080

Yellow Warning Sign — Dramatic, Digital Art

1627 × 1050

Space Battleship Firing Laser

4096 × 2304

Yellow Warning Sign — Black, Serious

1920 × 1080

Yellow Warning Sign — Dramatic

1920 × 1080

Dubstep Zone Warning Sign

1920 × 1080

Futuristic Spaceship — Purple, Dramatic, Night, Digital Art, Stars, Space

1920 × 1080

Red Warning Tunnel

1366 × 768

Black Textured Background — Warning

1920 × 1080

Yellow and Black Stripes — Warning

1920 × 1080

Radioactive Warning Symbol — Yellow, Dramatic

1152 × 864