The glyph/code spells out HEARTS. The last glyph replaces the normal dot with a heart symbol.

Olivia: So, what was so important?
Walter: Hmmm? Important? Breakfast. The most important meal of the day. And I proved it in 1973. Blueberry pancakes. A Bishop family specialty, best eaten while it's still warm.
Olivia: Walter, you didn't have to do this.
Peter: That's exactly what I told him.

Peter: I know that you struggle with trust issues. That you have a difficult time letting people in.
Olivia: Well, I... I'm struggling because the reasons are real. I'm not making them up.
Peter: I know. I never wanted to be one of the reasons. And I still think about her, because I spent so long imagining going down that path with you. Imagining what it would be like to wake up in a bed next to you. To sit around, just the two of us having a cup of coffee, reading the paper. And then finally, I had it. I've seen what the two of us together looks like. And it's beautiful.
Olivia: Peter, she's the one that took it away from us, not me.
Peter: And now? Who's the one stopping us now?

Peter: Hey, Cupid!
Walter: Did my plan work?
Peter: Well, if your plan was to make things even more awkward and painful between Olivia and I, yeah, worked like a charm.
Walter: Perhaps I should have made a frittata.

Peter: Walter, we keep 'em in the back.
Walter: Then why are you all sitting around?
Astrid: I'll go get it.
Peter: You know, a thank you wouldn't kill you.
Walter: Oh, I'm sorry if at this moment, when the universe is collapsing, I forgot the magic word.

Olivia: Do you really think that this is the end of the world as we know it?
Peter: If it is, there's no reason to wait outside in the cold for it. There's a bar right across the street.
Olivia: Wait, you think that now's the time to be throwing back shots?
Peter: Who said anything about donning shots? Maybe they got fries.
Olivia: Now you're talking.

Peter: Did I ever tell you about the time Walter did his rendition of Never, Never Going to Give You Up?
Olivia: No, but I actually love Barry White.
Peter: He was only wearing his socks at the time. Doing the Hustle, there was a lot going on.

Broyles: I need to run this up to channels.
Peter: Not exactly how you imagined meeting the President, huh?
Broyles: I already know him. He doesn't like me, I beat him at golf.

When Walter strikes the glass, a star-shaped design with two arms on the top is created. When the camera cuts to a reverse shot, the star-shaped design only has one arm at the top.

The Observer can be seen walking by Craig and Sylvia, his back to the camera, as they walk down the street toward the Rosencrantz Building.