Refresher: Brad, Frank-N-Furter, and Riff Raff are in the laboratory when the monitor reveals Dr. Scott entering the castle. To skip a chase scene, Frank activates the Triple Contact Electro Magnet, drawing Dr. Scott’s wheelchair on a comically twisty route through the castle to the magnet. (Look close and you’ll see both the wire pulling Jonathan Adams and the carpet separate when he gets near the top.)

It’s hard not to linger on the litany of ways this defies physics and…you know…reason, but let’s stick to interface and interaction. The main control is a lever that slides along a channel that runs a third of the way horizontally, then downward diagonally for the middle third, and horizontally again for the last third.

When Frank pulls the lever to the right, the first contact (the v-shaped electromagnet) extends away from the wall. When he pulls it along the slope, the second contact extends. The last slide right extends the third. Across all three, a humming sound in the background increases in intensity.

After sliding it all the way to the right, Frank raises a heel to the corner of the panel, and we see the magnet take hold of Dr. Scott’s wheelchair. This may be more than posturing, see below.

A subtle character clue

In the vivification scene, Frank-N-Furter shouts orders for minions to carry out. Here he grabs and manipulates the machine himself. As I noted in my old Presidents Day post, it is a mark of authority to be the one issuing orders but not carrying them out.

Frank’s use of machinery here signals both his increasing paranoia and decreasing regality. Riff Raff’s betrayal cannot be too far off.

Oh, wait. I said I’d focus on interfaces.

Right is more is right

Unlike what we see in the monitor and vivification interfaces, here the mapping makes much more sense. This is an English-speaking movie, and for this audience, right equals more is the natural mapping. So props where it’s due for that. As Frank moves the lever to the right, more contacts engage, we hear more humming, and more targeted cartoon magnetism is caused.

{Umpromtped image: Imagine a Tex Avery-style illustration of Frank-N-Furter from The Rocky Horror Picture Show holding three gigantic U-shaped magnets in his laboratory. Leather jacket with studs and chains, fishnets. --ar 16:9}

Selection is missing

Surely there are other metal objects in the castle that would become bullet-like projectiles the moment this was activated: the studs on Frank-N-Furter’s jacket, the anklet he wears (which, ok, might be silver), Dr. Scott’s glasses, the record player in the room where Columbia and Magenta sit, etc. etc.

If the magnet is strong enough to pull a wheelchair through a masonry wall across two floors and at least four rooms, you would expect it to attract other things as well, but…[FX: cricket sounds].

If we presume that the magnet can somehow target objects and leave others alone, there should be some interface for allowing the user to name or specify the object to target. That’s fairly easy to do in a 2026 world of foundation models, speech-to-text, and computer vision, but would have been a major challenge using 1975 technology. I’ll discuss some speculative solutions for this in the upcoming post about the Medusa interface, but in the meantime I leave it as an exercise for the reader.

The guided channel

A plate with a channel cut in it, through which a lever slides, is called a guided channel. The channel guides the motion of the lever.

The control for the Triple Contact Electro Magnet has a guided channel, and it borrows from lineages of the automotive gear shift. A manual gearbox’s H-pattern (variation pictured above) is mechanically determined: the channel is a map of the shift rails underneath it. The automatic transmission’s staggered gate is the opposite, that is, a later addition that was retrofitted for error prevention.

Either way, a bend in the channel buys some things.

1. It allows confident mode selection by turning each distinct position into a pause point that you reach by pushing until the lever stops, so you don’t need to know your current state before you shift, and you don’t have to commit attention and fine motor control to arrest the motion yourself. In this case, every switch sits at an obtuse corner, and that corner interrupts a directional push. This effect would be even more pronounced with 90° or acute angles. Note Frank does not look at the control as he uses it, because he doesn’t need to. He can feel it.
2. Additionally, the bend puts a safety barrier between states that are dangerous when adjacent. In a car that helps avoid accidental shifts from, say, fifth gear to second, where you might seriously redline the engine. Or worse, if you slipped past neutral into reverse while traveling at speed, your transmission might end up in parts on the road beneath you. That’s the reason regulators require neutral to sit between drive and reverse.

And, sadly, none of these things matter in this context.

• Since the magnetic effect can be targeted to individual objects (no other way to explain the basic events on screen), there’s no apparent cost to setting it too high. So, mode selection isn’t precious.
• As a status indicator, it’s redundant. The extended contact is a second cue and the sound of the system a third, and there’s no evident penalty for overshooting to full power. Generally speaking, a bent channel earns its place when use is fast, habitual, and eyes-free. I cannot imagine what regular use of the Triple Contact Electro Magnet might fit these requirements.
• This is less like a gear shifting through different modes and more like a volume control with four steps (off being one). There are no modes that are dangerously adjacent, so the functional pause isn’t warranted.

So the interface is doing something it absolutely doesn’t need to for any functional reason. Sorry, Frank.

No, not the Triple Contact Electro Magnet!

But what it does do very well is drama. Like, you can imagine alternate interfaces:

• A four-step dial with stops at either extent.
• Three toggle switches, one above each contact.
• Illuminated buttons above each, similar to the proposal for the The Reactor Power Input.
• Even manual pull bars on the contacts, like you see on an airline serving cart, would do the trick.

But none of them give Frank and the other Transsexuals as much opportunity to be over-the-top dramatic as they crank the magnetism up, up, up. That’s impressive for victims (and conventioneers, if they were around), and perfect for Frank’s theatricality.

So even though this control isn’t really warranted, from a functional standpoint, it totally is from the users POV.

Bonus: What if Frank’s not just posturing?

Hear me out on this bit. It’s curious to me that the magnets don’t seem to have any effect on Dr. Scott until all three are extended, and, when they do, they function all at once. Sure, it’s editing convenience, but what if it’s something more? What if Frank’s heel pose is not posturing—well, ok, it’s posturing, but what if it’s also authentication? Imagine a passive RFID key located in Frank’s high heels, and the detector mounted in the plating. (Or maybe the detector is the plating.)

This would help Frank feel more certain that it can only be operated by him, or at least someone in possession of the shoes. Since the key is disguised, it adds to the security of the interaction. And its activation requires a heel up, which as we’ve seen is a standard Frank move. It would also explain why despite having activated the Triple Contact Electro Magnet to full power, it only takes effect all at once when Frank’s heel activates it.

And if you weren’t aware, interaction design of women’s footwear is kind of a thing.

So now this activation mechanism is my headcanon.

There’s one more set of interfaces that go together, and they’re next. Transducer, Medusa, and de-Medusa (currently scheduled for 29 Sep 2026)