
Penny was the teacher.
When the light turned YELLOW...
The Big Bang Theory Season 3, Episode 16

You can't cross
a double YELLOW line.
The Big Bang Theory Season 12, Episode 14

Yellow. Go ahead.
The Big Bang Theory Season 4, Episode 22

...YELLOW is frightened...
The Big Bang Theory Season 4, Episode 22

Where's the other one?
The one with the YELLOW cloak.
Game of Thrones Season 6, Episode 8