The pendulum swings in a circle if you're lying and a line if you're being honest. Sometimes, it even works.

Sadly I am having a great deal of difficulty uploading the largish .zip file which contains my five videos; for some reason the computer keeps failing to actually do so, and when I try to send them to my media folder I click "send" and am told by gmail that "the document contains no data".

If I ever do succeed in uploading the videos, probably by trying from somebody else's computer, I will of course share the results by editing this proof, but for now let us be content to read the following transcript from one of my tests:

Peter Harmon: I would like you to tell me what you most enjoy spending Sunday afternoons doing.
Random guy I know: Well, generally, I like to go to the moon.
(The pendulum is not yet responding.)
RGIK: The moon's a lot of fun. There's good moon rocks to eat, and generally it's kinda greenish...
(The pendulum starts swinging in increasingly-large circles.)
RGIK: So usually I go there for, y'know, picnics.

PH: OK. Um, I'm gonna stop that...
(I stop the pendulum.)
PH: ...and, I would like you to tell me about your pets.
RGIK: My pets? You see, I have one large dragon. His name is Reginald.
(The pendulum starts swinging in ever-growing circles.)
RGIK: He really enjoys tea and crumpets. They're his favorite foods in the world. And then I have a rabid wolf -
(The pendulum suddenly starts swinging back and forth, confirming this part as true.)
RGIK: His name is Tigger. And, I guess I have two cats; their names are Cool-Eye and JD.
(The pendulum is still going back and forth.)

PH: Good to know. Um, that's very interesting, as it appeared to register a lie about your dragon Crumpet (ed. note - I had misremembered this as being the dragon's name rather than his favored food) but that the other three were real. Um
RGIK: I might have a wolf.
PH: Apparently you have a wolf and two cats. Is this correct?
RGIK: Yes. Definitely.
(I stop the pendulum.)

PH: So... what inspired you to pursue a carreer in piracy?
RGIK: Well, see, my dad was a pirate. And my mom, she was sort of a pirate. And really, together, it's a winning combination.
(The pendulum begins making small circles.)
RGIK: And about when I was thirteen I met Blackbeard, and man, he really inspired me. Truly an inspiration.
(Huge circles now.)
PH: Yeah, yeah, that's a lie.
RGIK: (inaudible)
PH: Yeah, I do, and -
RGIK: Is that good?
PH: Yeah, that should be -
(The audio cuts off here, but the video continues for half a second.)

As we can see, this lie detector has a higher reliability even than a polygraph - as it caught all three of RGIK's lies. I was later able to confirm that he was in fact lying about the moon and piracy, and that he does not really have a dragon; as he confirms in the interview, the pendulum was correct in saying that his rabid wolf Tigger and his two cats Cool-Eye and JD all exist.

Cool-Eye may be the best cat name ever. But there's a chance I misheard it and it's something less awesome. Regardless, I want to meet this cat. And Tigger, of course.

EDIT: I have subsequently learned that the cat's name is in fact Kooa, not Cool-Eye.

EDIT 2: RGIK is now a player here on SF0! Everybody give a warm welcome to Quincy Potts.