The glyph/code spells out CROSS.

Bolivia: You have a lot of questions. I understand. But you can understand that I can't give you the answers.
Peter: This from the woman standing in front of me in pajamas who just shared the same bed with me. I guess answers is where you draw the line.

Walter: in the 70s, I innocently wandered into the wrong home, and it was three days before I realized my mistake. And unlike Olivia, the woman with whom I was sharing a bed didn't look like my wife at all.

Walter: I'm a fraud. A failure. Four hours of intense meditation augmented by a precise two-gram dose of Brown Betty and I've got nothing.

Walter: And I have no idea how to bring our Olivia back. It's all because of that temptress. She tricked my son with her carnal manipulations and he feel right into her vagenda.
Astrid: "Vagenda"?
Walter: Like Mata Hari using her feminine wiles to accomplish her evil ends. And I too fell prey. She used my stomach to get through to my heart.

Colonel Broyles: I have a decision to make.
Diane Broyles: Okay.
Colonel Broyles: Remember when I joined Fringe Division?
Diane Broyles: Mm-hmm.
Colonel Broyles: Two weeks into the job, we had that vortex in the East River. A hundred and sixty-five people swallowed up, half of them kids. But now we may actually have a chance to put our world back together. Fix it. Only thing is, to do that, we're gonna have to go to war. A lot of lives will be lost. An unimaginable number. And I don't know if I can live with that. There may be another option. But it could put everything at risk. Either way, who am I to play God with other people's lives? Who am I to make that choice?
Diane Broyles: Twenty years ago, I knew that you were the right man to protect our world. After all those years, I've never stopped believing that. I think this world is in as much pain as it can stand. We need to restore hope.

The Observer can be seen outside of Penn Station, right after the screen transitions from the Other Side. He is in the lower right behind a taxi.