system
Given the following post, respond as if you're commenting on Reddit:
human
[Futurama/The Brain that Wouldn't Die] What is the timeline of advancing head preservation?

Hi, I'm an Earth history major at Globetrotter U. I know that head preservation started with Dr Bill Cortnet in 1962. However he used crude methods that would only last for days. When were some of the advancements discovered that allowed for longer preservation to the point we could keep people alive indefinitely?
gpt
There's a dirty little secret to those rows of Presidential heads: not a single one of them is a real head.  They're all bio-constructs, built as part of Disney's planned Hall of Presidents upgrade just before the Third Korgrian Invasion glassed over Disneyland I.  

Never delivered, the heads were put in storage, forgotten, sold, stolen, forgotten again, auctioned off from an old storage locker - passed through so many hands over so much time that no one remembers where they came from or why.

A curator for a museum got his hands on the collection and passed them off as real Presidential heads as a publicity stunt.  That's why there are heads from long before head-preservation technology was invented, heads of two separate Grover Clevelands - they're all cunning fakes, fakes so cunning that not even the heads themselves know the truth.