I've known since the "Director's Cut" that Ridley Scott always intended to hint that Harrison Ford's character in Blade Runner was an android. I never got why, though.
It's all about that damn unicorn.
In one scene, Ford's Deckard is falling asleep and has a dream about a unicorn. It's not really important to know why he's dreaming of a unicorn or what the unicorn represents. Just know he's dreaming about a unicorn.
Throughout the movie, he is "handled" (in a CIA kind of way, as opposed to a Catholic priest kind of way) by a cop played by Edward James Olmos. His character speaks a pidgin language and is strangely fond of making little origami figures and leaving them around. It's not really important to know why he makes origami figures. Just know that he makes them.
At the very end of the movie, after the unicorn dream, after tracking down and killing all the rogue replicants, Harrison Ford is leaving his apartment with his replicant girlfriend and finds a tiny little unicorn origami figure in the hall.
You see, the unicorn dream wasn't a dream at all. It was a memory implant. And that unicorn origami figure in the hallway was just Edward James Olmos's way of saying, "I know you were implanted with a unicorn dream."
Makes sense, right?