I wrote this account of an encounter with Penn and Teller fairly soon after it occurred in 1989, and haven't edited it except to add HTML markup. So words like "recently" have to be understood relative to late 1989 or early 1990.

Although it's barely mentioned in the account, the whole thing was recorded on multiple videotapes with an elaborate though amateur setup. Later Teller came back to the Labs once or twice to tape the intro and voice-over of the story by me, in order to create a coherent video. I was not a good narrator or TV actor, and (to my relief) Teller decided to enlist Penn to do it, with a script from P&T's perspective instead of mine. This worked much better. The material was rather nicely edited, given its sub-broadcast quality. The tape was shown at Usenix conventions, and clips were shown during Arno Penzias's retirement observances.

This video was digitized (2002) by Gerard Holzmann, and is available as a big (88MB: caution!) MPEG here.

The reference to a treatment "by a better author" had to do with an article that Penn thought of writing, but didn't, so far as I know. Accounts of the story did appear in the Wall Street Journal, but by the paper's own reporter, and also in Wired.

Rob remains pretty close to Penn Jillette; in turn Penn now and then drops Rob's name.

Amongst the unmentioned bennies I got out of the experience is a gift book from Penn: Darwin's Thumb Tip Miracles, forward by Siegfried and Roy. Penn was kind enough to inscribe it "Dennis-- on to magic trips of many nations. .... the Roy of Penn and Teller. -- Penn." Oh yes, and also a lifetime supply of thumbtips, which my relatives are now more than hip to.

Labscam--A Preliminary Report
Dennis Ritchie

This is a brief account of an interesting practical joke we perpetrated recently. A better treatment by another author will be forthcoming, as will a video. I will tell the story in linear fashion as a straight history, instead of striving for dramatic effect.

In the fall of 1989, Rob Pike met Penn Jillette, of the comedy/magic team of Penn and Teller. The introduction and initial conversations were through e-mail, and the mutual acquaintance who started things off was Mike Hawley, now enmeshed at the Media Lab at MIT. After a series of electronic letters, Rob attended one of Penn's Friday movie nights, which was just as described by Calvin Trillin in his recent New Yorker profile of P&T. (Meet in the Times Square HoJo's. Rob wondered, `How will I know you?' and Penn said, `I have samurai hair and I'll be at the back.')

Penn's interest in visiting Bell Labs had already been piqued not only by Hawley, but also by Ron Graham (BTL mathematician/juggler), another mutual acquaintance. By the time Rob met Penn, thoughts of something more than a mere see-the-sights visit began to stir: there was the possibility of pulling off a great trick.

Who should be tricked, and what should happen? There was only one possible target--Arno Penzias. He satisfied simultaneously all the desirable criteria: stature (Nobel prize laureate and Vice President of the Bell Labs Research area); ability to be tricked (he trusted us and liked technology); challenge (he's smart); and, we hoped, appreciation of the effect. It was known through Graham that Arno was a great Penn and Teller fan, and it was worth gambling that he would feel flattered rather than anguished at being fooled.

Rob's meetings with Penn and then with Teller (at the Tarrytown HoJo; Teller is less urban, though more urbane, than Penn) soon produced the bare outlines of the scam: Arno would be shown a demo of new work that Rob had supposedly done, probably involving communication with a computer program that somehow impersonated Penn and Teller. Rob arranged to visit their office in New York to work out the details.

Initial ideas depended on explicit stage magic. For example, Arno might be induced somehow to put his badge or his driver's license in an envelope; through a slit in the envelope, the document would find its way into the next room. At the climax (`reveal' is the technical term), P&T would bounce in, bearing the document.

At this point, I had an evil thought. Why not work out a double-cross? Suppose the trick depended on sneaking Arno's driver's license to P&T; what would happen if we prepared a shoddy, manifestly fake Arno license, and sent that into the back room instead? Or what if Penn and Teller came bounding in to confront Arno, but there was no Arno there, just a computer? Rob was sufficiently taken by this scheming that he invited me to the New York meeting.

During the meeting, the Tuesday before Thanksgiving, the first thing to become obvious was that no explicit magic trick could be plausible; instead the presentation would have to appear strictly technological. As we worked out the details of the final plan, it also became evident to Rob and me that all thoughts of a double-cross were inappropriate. The scheme was so strong that it couldn't be turned around without ruining it. We returned home in high excitement. On the Sunday after the holiday, Penn and Teller came out to Bell Labs to run through some rehearsals and finish the script. They also got a tour of the facilities, and saw at least some of the real stuff here. That evening, we set up the technical aspects of the demo, and also placed hidden video and sound equipment to record the event.

I decided to pique Arno's interest, and so sent him some mail:

	From dmr Mon Nov 27 02:37:04 EST 1989
	Subject: voice stuff

	I think Rob is almost ready to invite you to
	look at his latest effort, which is (pretty much)
	voice recognition.  He's able to show surprisingly
	good results from a fundamentally simple-minded
	scheme; it's worth seeing.  Besides, he appears
	to have spent the long weekend putting some pizazz
	into his demo; he claims it is like Eliza (esp. the
	"Doctor" program) for the multimedia age.


I sent a copy to Rob, and he replied, `Uhhh, I guess I'm committed now.'

The next day was the demo itself, which was scheduled for 2:30. Penn and Teller arrived in the morning, and we rehearsed a couple of times, using an Arno substitute. Unfortunately, Rob had not made a firm appointment for fear of tipping his hand too soon, and Arno managed to become involved in business. So we had to wait throughout the afternoon; by this time, 6 or 7 people were directly involved in the production, and even more were in the audience. Penn and Teller repaired to Ron Graham's office to talk magic while the rest of us waited nervously; P&T came back; Penn told us the blood-curdling tale of his attempt to jump over five Volkswagens on a rocket-powered unicycle, and the ensuing attack by a riotous mob; Teller taught sleight-of-hand. Finally at 5:30, Arno was successfully fetched, and the show began.

It took place in our Graphics lab, a large room partitioned by a soundproof screen. Rob ushered Arno into the smaller half, and sat him in front of two terminals. A bright light shone in Arno's eyes, a microphone and TV camera were inches from his mouth. On one terminal, a real-time, processed image of his lips appeared. On the other were printed several words.

Rob explained that he had been trying work in speech recognition, and had achieved some interesting results. The camera was watching Arno's lips to help determine when he was speaking, and the computer would analyze his utterances. It would first be necessary to say each word in sequence, so as to train the recognizer to Arno's voice.

So, Arno said the first word, "Hello." Rob typed stuff on a third terminal. On the terminal Arno was facing, things flickered, and a graph and some numbers (`autocorrelation coefficients') appeared. Arno said, `Sanskrit.' More flickering, graphs, numbers. Arno said, `Hohokus.' Initial training was complete, and all participants but Arno grinned secretly. Penn had predicted, `If we can just get Arno to say ``Hohokus'' into a microphone, we have won already!'

The words disappeared, and several sentences came up on the terminal. Arno had to pick one of the sentences, and speak it. Rob readjusted Arno's head to make sure his lips were centered on the TV. Arno said, `It's a pleasure having you with us,' and a synthesized voice said `Please repeat.' During this phase, the machine was supposedly deciding which of the sentences was spoken. Finally, it got this right, and Arno moved on to `Kenneth, what is the frequency?' After two tries, the machine repeated this too.

Now, Rob said, we can have some fun. No doubt Arno remembered Weizenbaum's famous Eliza program? It did simplistic processing on what was typed to it, and could pretend to be Rogerian psychiatrist. To bring the idea up to date, Rob had taken a videotape of the David Letterman talk-show, and digitized the guests' answers and the host's questions. Arno would play Letterman, and ask the questions; the machine would match each question to one actually asked, and then play back the appropriate answer. First, Arno had to select which guests he would like. His choices were: Mike Wills, author of `Dance, Dance, Dance, She Said,' or Penn and Teller, or Janet Kirker, from `Dynasty.'

Arno chose Penn and Teller.

First, he got a menu of preset questions. He spoke one of them (`Which is Penn and which is Teller?'). On his screen, after the graphs and numbers, a video image shuffled through several stills of Penn and Teller; finally an animated (though low-quality) image of P&T appeared, and a scratchy but recognizable Penn voice said, `Don't you learn anything? I'm Penn Jillette, and this is my partner Teller. Longer name, bigger person.' Arno asked several questions from this menu, and got responsive answers. `Does Teller ever talk?' `No, not to you.' Each time, the answer was accompanied by the corresponding sleazy video clip.

Finally, Rob invited Arno to ask questions of his own. This could work because the computer would search for spoken words and phrases among the stored clips. This time too, each question elicited a response, though some of them were peculiar.

`How long has it been since you became partners?'

`I think it was in San Francisco, about 1981... That's when Lou Reed came to the show...'

Rob suggested that Arno rephrase the question.

`How long have you been partners?'

`It's been 15 years of complete hell.'

`Have you won many awards?'

`Well Teller took the Obie, and he's going to win an Academy Award. Me, I'm holding out for a Nobel Prize!'

`What do you do with rats and cockroaches?'

`That's the way we have sex.'

Rob seemed embarrassed, and asked Arno to speak more clearly, keeping his mouth in the right position. `Do you use rats and cockroaches?'

`Oh, I like that on pizza, and Teller uses it on a hot dog roll, or a hamburger bun.'

At this point, Rob looked flustered, and suggested that Arno ask Penn and Teller to show him a trick, because they did a good one on this show, and the computer would show it.

After one peculiar reply, the Penn image announced, `Well, we hung upside down on Saturday Night Live, and we dumped cockroaches right here on your show. But come with us, we have something special for you. Could the camera go hand-held?'

P&T got up, and the camera followed them into a strangely familiar corridor. Penn continued, `Let's go down this hall here. We've done a lot of stuff on television, and TV is not the most conducive medium to magic. We wanted something where things would seem to go from TV into reality.'

They opened a door, and Arno saw a man sitting in front of several terminals, with a light shining into his eyes.... `So we worked out this little thing where a person was watching a video screen, and we could actually come in and interact with the person....'

Then Arno turned around, and was confronted by Penn and Teller!

The effect was lovely. An amazing thing about it is that not only Arno himself at the time, but nearly everyone else who hears about the story, finds it hard to accept that it was ALL a scam! While Arno was saying words and sentences, I was in the back room controlling what he saw and heard. The `video clips' were live pictures of Penn and Teller, turned on at appropriate times.

And fortunately, just as we had prayed, Arno did feel flattered, though at first he was quite jangled by the experience. After he took Penn and Teller to his office to chat, he uncharacteristically forgot to give them 3K T-shirts, and someone had to dash back to pick them up!