Fringe Connections

In "Grey Matters" Walter's brain pieces were stored the heads of living people. In "Letters of Transit", in the altered timeline, they were stored in Massive Dynamic.

Olivia pulled up a list of the frozen heads found in S02E04 'Momentum Deferred' and they were all marked with "2E204", a reference to the episode in which they were stolen.

The seahorse glyph can be seen as Olivia and Shapeshifter Charlie fight in the alley.

The translucent skin toxin from "Pilot" was used as a weapon against the Observers in "An Enemy of Fate".

The license plate on Olivia's SUV reads 1R2D21, and the licence plate on Broyles's SUV reads 1C3PO1.

The butterfly glyph can be seen near Lincoln in the rail yard.

The radioactive isotope compound from "The Cure" that caused heads to explode was used as a weapon against the Observers in "An Enemy of Fate".

The crane that crashed during the intro has a Massive Dynamic logo on it.

The flower glyph can be seen on the wall in the diner where Olivia and Lincoln meet.

Walter implanted a tracker in his neck in "Snakehead" which is used in "Grey Matters".

The yellow dot in the final glyph of the episode is replaced by a yellow heart.

A butterfly can be seen attacking Mark Young.

The intense amount of Cortexiphan coursing through Olivia in "Brave New World (Part 2)" was able to heal her mortal wound. This was foreshadowed in "Brown Betty" when Olivia was sliced by the same weapon that killed Rachel, yet instead of dying Olivia's skin started to heal itself.

All of the people in Olivia's mind wear blacks and greys because Cortexiphan subjects have a strong desire to blend in.

The apple glyph can be seen on the backrest of a chair in the lab.

The Observers read Nina's phone call from the impressions her sound waves made on the glass in her office in "Anomaly XB-6783746", like Peter did in to hear the phone call Nancy Lewis made in "The Road Not Taken".

Carr's work review sent to Astrid from his previous employer shows that in the three years prior to his dismissal, he only missed three days of work. He was out for only one day each year and each year it was the same day: Valentine's Day.

A frog can be seen outside the entrance to the daycare center.

Patterns drawn on cards from David Robert Jones's box of tests for Olivia in "Ability" bear a resemblance to the stasis runes used in "Brave New World (Part 2)". Very little is known about either.

Madison Square Garden in the Redverse is quarantined in amber.

A flower can be seen outside the entrance to the daycare center.

Simon Foster was trapped in amber in "Letters of Transit" and the Observers were experimenting on Simon's head in the Ministry of Science in "In Absentia".

When Nina looks in Bell's storage room for his copy of the First People book the camera pans by a copy of 'Dr. Spock's Baby and Childcare'.

The flower glyph can be seen as Olivia and Shapeshifter Charlie fight in the alley.