Letters and Numbers

An index points. We might think of the index as an outstretched finger directing the way. (This is how the first finger on each hand got its name, the index finger—the one that points, that indicates, makes known). Or, it is a list in the back of a book that directs you to the correct page number to find the information you require. In 19th-century semiotics, philosopher Charles Sanders Peirce sought to formalize a way of thinking about signs as a continuation of his studies in logic. He wrote about the icon, the index, and the symbol. The icon physically resembles the thing it stands for (a small picture of a plane stands in for the plane itself) and the symbol points to connotations (usually word-based, but also in the sense that the bald eagle is also a symbol for the USA). However, the index is a sensory feature that correlates and implies something else. The classic example of an index is the presence of smoke, an index of a nearby fire.[1] Though it may have been unintended in its original design, the rhythmic clacking of the Solari display also has this signifying effect. Its cascade of clicking turns faces upward. The noise of the circulating flaps acts as an index—it points to new departure and arrival information. And maybe this indexical noise can’t be underestimated—when Boston’s Massachusetts Bay Transportation Authority replaced their split-flap displays in 2006 with digital LED displays, they retained the noise of the analog departure board:  a tick-tick-tick emitted by a speaker system inside of the board when the schedule changed over.[2]

In addition to the rustle of letters, there are a few other factors that make the analog split-flaps appealing (aside from retro-nostalgic longing, which is patently undeniable and yet perhaps a whole other story). Unlike digital displays, which become washed out and hard to see in bright light, and can only be read when regarded straight-on, the high contrast white-on-black letters of the Solari display allows for higher visibility in most light conditions. It is also able to be read from many different angles—which is useful in airports and train stations, where people are dispersed across the arrivals and departures area. Additionally, unlike a LED display that must remain lit when it is static, a split-flap display uses very little power until it is instructed to flip. And if power is cut temporarily to the system, the information remains visible instead of falling dark and then resetting in a jumble when the power returns.

Although we’ve delved mostly into the visceral mechanics of wiring and breadboards so far, the flaps themselves are the capricious face of each display. Originally metal and later plastic,[3] they came in the form of a fixed text (the whole name of a station or an airline) or an alphanumeric display that could be programmed individually. They would have been industrially cut and silk-screened in sheets. This was complicated in terms of individual replacements. As Tom Chaffin, the acting Principal Engineer for Telecoms at Thameslink writes of the fixed text displays, “every time the timetable changed altering train service calling points or final destinations changed or even for a train company name/branding change, new flaps had to be silk-screen printed and then inserted into the indicators ideally the night of the timetable change.”[4] With an entire rail or airport system, this process was costly and time-consuming. As a person responsible for the twice-yearly updates for the Southern Regions rail system reminisces, delivery took about 9 months, so you would have to predict requirements a year in advance. However, he notes, they could also order the flaps in multiple colours, and even could use the “rest position” as an advertising display for newspapers and whiskey.[5]

Black and white split flap board showing fixed and alphanumeric flaps from Kagoshi, Japan, small pink flowers in front of it, and airport arrival information on the boards.
Wikimedia Commons, “Split-flap display in Kagoshima airport, Kirishima, Japan.”

We’re working with two arrivals/departures displays—relatively small ones in the grand scheme of the giant multi-city boards Solari has manufactured—each display has eight cartridges, each cartridge has 40 cards (and how many were there going to St. Ives, I wonder?).


The first six cartridges in each board are 2-inch alphanumeric displays, followed by two larger cartridges to display a 24-hour clock. Inevitably, just in the ordinary course of their use—to say nothing of the subsequent closure, abandonment, and decay of Mirabel—at least a few flaps would have gone missing. We had to get an overview to make sure we had a full set. Earlier this summer, I flipped through what should have been a total of six hundred and forty flaps, so we could make sure that we had a complete set. Incredibly, we’re only missing two.

I wrote earlier about our makeshift replacement flaps in this post, laid out in Adobe Illustrator and sliced from the matte black plastic file folders Matt had found in the Loyola Campus bookstore by Mark’s laser cutter. Next, we needed to get the letters printed onto the black plastic. In an early experiment, I wondered if we might be able to paint the letters on with a brush. It seemed like the best choice to start, given that we only needed two flaps. I marked off the bottom half of the test B with painter’s tape and gave it a go. However, when I carefully tweezed off the tape after the paint was dry, the results were less than inspiring. The edge was a bit ragged from paint seeping under the tape or being pulled off in the removal process, and the brush marks bunched and stripped the paint in varying ways across the surface. So, we needed a different option. MIT’s The Beach Lab, in an effort to make their split-flap display relatively inexpensive, opted for cut vinyl letters. You can learn more about that project here. But I was so taken by the crisp edge of the screen-printed letters of the originals, and wondered if the vinyl letters might stick out sorely in a cascade of printed ones. It looks like others have done this method also—of cutting the flaps first and then individually screen-printing—like this dance company in preparing a board for a performance about travel.

My pal Justin Gordon is one of the three founding members of the excellent Montreal-based printmaking collective and studio Atelier Lost Cause, along with Concordia fine arts students Gabrielle Mulholland and Hillary Barnes. I asked him if he could help us out with printing, and he said he could try. I’d traced both sides of our missing letters (top of an E/bottom of an F and top of a Z/dash) at the lab and taken them home with me. In order to screen print, you need the parts you want the colour to go in jet black, and the other parts white. I took the original layout of the split-flap I’d made in Adobe Illustrator to use for the laser cutting:Black and white outline of split-flap…and repurposed it for our four half-letters. I carefully measured the tracings and laid out the letters in Illustrator, filled them with black, and printed them out on ordinary paper (with back-ups—in case one of them didn’t work out).[6]

Overvew of four black-and-white letters with blue split-flap outline laid out in a grid. The top of an E, bottom of an F, top of a Z, and a dash.Justin laid all four letters out with oil on one screen, exposed it, and then we were ready to go. We laid down a test onto acetate so we could see where the print would land, lined up each black flap behind the acetate, and printed the letters. They were a bit sticky when they came out, and so we tried to dry them under a heat dryer, which resulted in melted plastic. A brief stint under the dryer, and then some time by an open window, and they were ready to print the other side. Here they are—crisp, clean, and smooth, and although the gloss of the letters isn’t exact, it’s a pretty good match.

[1] R. Port, “ICON, INDEX and SYMBOL (Short Version),” http://www.cs.indiana.edu/~port/teach/103/sign.symbol.short.html.

[2] Mac Daniel, “Nostalgia for noise at South Station,” Boston Globe, 6 April 2006, https://www.ble-t.org/pr/news/pf_headline.asp?id=15901.

[3] http://www.iridetheharlemline.com/2010/05/14/fridays-from-the-historical-archives-solari-departure-boards-photos-history/

[4] http://unknowndomain.co.uk/category/design/split-flap-display/page/6/

[5] http://www.railforums.co.uk/showthread.php?p=2255362

[6] I should have had both a copy with the outline of the flap for a guideline and one without for the printing, but I didn’t print the latter! This meant that Justin and I had to cut carefully around each letter, lest the outline of the flap be printed in white onto the edge itself.

Completing the Circuit (Board)

When Mark was in the lab last Thursday, he brought in the circuit with four cables attached. This was his first test with more than one alphanumeric split-flap display—a set of four, which we need to be able to program to display different letters. This will eventually lead to the final wiring of six letters and the two cartridges of the 24-hour clock display. After getting them to level out and running a few tests, we invited up Communications Studies’ own Douglas Hollingworth to see our run of four spell out his name. Here’s the wiring in action:

On our next test Mark moved on to try out his own name, but instead it flipped up as MORK. We guessed that this was because of the same dirty wheel conundrum we had with the new solo unit last week. We cleaned it off again with a little rubbing alcohol, reconnected it, and this time, it flipped perfectly to MARK. Seems like we’re going to need to clean the wheels on all of the units to make sure the display registers correctly. (On a side note, is it just me or are these all-caps 4-letter names somewhat reminiscent of the demons of Twin Peaks?)

Confident now that the board configuration will work for the Solari controller, Mark is now getting a PCB—a printed circuit board—made up. You’ll recall that Mark has been working from a large-size breadboard:

IMG_5946A breadboard makes it possible to plug in wires, capacitors, sensors, resistors, power sources, integrated circuits, diodes, and transistors and still move them around. It’s a temporary support consisting of a plastic board with rows of holes, and a metal backplate. The electrical parts are pushed through the board until they connect and hold with the metal plate. It’s a provisional circuit that can be tested, adapted, and moved around until you’ve got something you’re happy with. When I asked Mark about those two teal-headed pins in the center of the board, he told me that they’re used as placeholders. Sometimes you want to move a wire and try it somewhere else, but you don’t want to forget where it came from in case it doesn’t work and you need to move it back. The pin stands in and holds the place of the moved wire until you can confirm that the circuit will work in its new configuration.

Historically, breadboards were actually that—boards for bread. Electricians needed a way to affix and keep steady a circuit involving tubes, lights, transformers, and other large components. They would screw these components and wires into the board, and would be able to unscrew them and move them around as needed during the testing process. Check out a picture and more information here.

However, once the circuit is complete and ready to be used, the breadboard makes it very difficult to practically use. Though temporarily secure, wires can get fall out, the long metal arms of capacitors and resistors can lead to crossed wires, and the whole shebang can get tangled and messy. So, once your circuit is fixed, you can print a PCB, a circuit board which has all of those components, just laid out flat on a piece of non-conductive material. Wires are printed as copper lines, and other parts are soldered onto the board.

Our PCB will have our names silkscreened on it—Spikenzie Labs as the designer, and Flight YMX – Montreal Signs Project as the initiator. Like the small yellowing tag, written in Italian, that points towards the boards’ origin in Udine, this PCB will be our trace in the board, the index towards this project—this time and place.

Speed Test, Dirty Wheel, Laser Flaps

Mark has been working away, and we’ve been able to troubleshoot some of the action on the Solari displays. When I went to visit him at the Spikenzie Labs workshop, the first thing he showed me was a speed test. The Arduino system is able to control the flapping speeds as well as which numeral/letter comes up. Actually, it controls the millisecond delay between the turning of the flaps. We have a lot of play with how fast it will be able to go. In this video, Mark tries three flapping speeds—one slower, one standard speed, and one fast. We could go faster or slower, but if it goes too much slower it could fry the motor, and if it goes too much faster it could overheat! Some of these other home-made models are faster paced than the standard Solari board, but the artist we work with will need to determine how fast they want it to go.

Next, I had brought over a different unit so we could test it out with the system Mark’s been working on to make sure there wasn’t a difference between the units. We hooked it up to the board, and it seemed to be glitching—when we set it to flip incrementally one by one, it was working fine, but trying to skip from the neutral position to a further ahead letter, it was falling short. We tried from a few different angles, but nothing was seeming to work. Finally, Mark had an idea—that the wheel was dirty! The wheel knows how to display the numbers based on the differential between the metal plates and the fiberboard wheel. It was falling short because it was registering the dirt on the metal plates as the fiberboard. He gave it a scrub with some rubbing alcohol and set it straight.

We’re also missing two flaps (Which from 8 sets of 40 flaps per machine is a pretty good rate!), and I’ve been working on replacing them. Matt had found a black plastic folder in the school bookstore which is about the same weight and colour as the flaps in the machine. We were worried at first that it would be too glossy (the flaps themselves are smooth and matte) but after holding them up next to each other, the match is pretty convincing.

We wanted to try laser cutting them so we can have a few back-ups, or so the artist we work with could potentially play around with different signage by replacing the flaps, if they wanted to. I did a burn test on the plastic, which makers will know is essential for laser cutters—if the flame is green, the plastic has chlorine present, which releases a gas. Not only is the gas toxic to the people laser cutting, it also has a damaging effect on the machinery itself. Blissfully, the flame was orange and not green! We carefully measured the dimensions of one of the existing flaps, and then I mocked it up in Adobe Illustrator. We sent the AI file to the laser cutter. After a few tries (the first ones were too slow, and melted the plastic) we came up with a clean, beautiful, laser-cut flap. This is totally exciting! Next, we’ll start work with a screen printer to print the missing letters on them.


Connections: DINs and Wires

The guts of our Solari displays are a twisting rainbow of bright wires on the pale yellow paint of their metal shell. Mark, our man at Spikensie Labs, came in last week to have a look at the innards in order to see how the circuit he’s making will line up with the structure itself. First, he was interested in testing out the connectivity of this patch panel, which in the original Solari configuration would have connected the 8 cartridges of letters and numbers to the programming unit. He was thinking that if the patch panel worked, it would be possible to connect our remade programming to the existing hardware of the unit.IMG_5798

He attached power one by one to each of the six wires running from the back of each DIN-6 connector and ran the detector along the back of the panel looking for where the electrical feed was appearing. No such luck! For each wire, we got connectivity only 20% of the time. We took a look at the rest of the unit, and it appears that the signals connect to the patch panel through a series of four relay boards, which are currently interrupting the electrical flow.


For those of you who like me are not-yet-versed in all matters electrical, a DIN connector is a form of electrical connector consisting of multiple pins within a protective circular sheath. It was initially standardized by the Deutsches Institut für Normung, a German standards organization—the German member body of the ISO (International Organisation for Standardization). As a term, DIN is less about cable type and more about standardization requirements. However, many DIN connectors consist of a round plastic sheath and a metal skirt, which keeps the sheath in place for a proper non-damaged connection.

Developed in Germany, the connector gained popularity in the 1970s as a standard connecting device for audio equipment. Possessing the ability to carry many independent signals, it enjoyed use in electronics until the mid 1990s when changing technologies meant that fiber optic cables and other new mechanisms began to be more efficient. Still, those of us who have connected a microphone or a speaker might notice a trace of the DIN’s physical resemblance in the still-prevalent XLR cable commonly used for recording and stage performance equipment. (A fun even-further side-note: the XLR gets its name from its development history from the Cannon X connector, to gaining an L with a subsequent latch locking mechanism, and an R with its rubber coating.) In our case, the DIN connector would have been a very popular piece of electronic equipment in 1975, when these Solari displays were manufactured for the 1975 opening of the Mirabel terminal.

After some testing, Mark noticed that the black plastic part in the DIN-5 connectors he had were very similar to the connectors in the panels, though the metal part wasn’t. This is a tricky business, because the slots on the DIN needs to match perfectly with the pins on each display cartridge, sliding in and lining up exactly with the connectors. We tested the plastic part, and it’s an almost-perfect match—the originals are 7 mm and the new plastic parts are 7.09 mm.
The plan now is to unscrew these two screws in the body of the Solari machine, use the guts of a new DIN-6 plastic part, and 3D-print a bracket to hold it (NB: for testing purposes, the photo is of a DIN-5 connector). Mark’s plan is to unscrew the existing plugs and tuck them into the panel—we’re trying to be as non-destructive as possible so that someone could choose a different restoration method in the future. Then, we’ll screw the new plugs and brackets into place with new wires connecting to our controller, completely avoiding the patch panel and the existing wires.


Works cited and further reading:
Meg Higa, “What Is a DIN Connector?” edited by Shereen Skola for wiseGeek, last modified 26 June 2016, accessed 27 June 2016:

Ray A. Rayburn, “A brief history of the XLR connector,” 4 July 2013, accessed 27 June 2016: http://www.soundfirst.com/xlr.html.

Preservation and Nostalgia

I remember hearing, long ago, about an audio recording project. My dad told me about it after reading an article in the paper. Someone was recording clips of audio of sounds ‘on the verge of extinction.’ It was a project wrapped up in nostalgia bent on capturing and cataloguing different noises. A museological archive project, one that lamented the disappearance of certain sounds, sounds the project’s organizer found beautiful and wanted to share with the ambiguous future. Among others, one of those sounds was the clacking of the split-flap displays changing over on the arrivals and departures boards of terminals.

Now that I’ve become familiar with sound studies, this initiative sounds a bit like The World Soundscape Project. Founded by Canadian composer R. Murray Schafer in the end of the 1960s at Simon Fraser University in BC, this international project sought to preserve sonic landmarks and dying sounds. Frustrated at ever-increasing levels of noise pollution in urban soundscapes and awareness that certain sounds were becoming obsolete due to changes in technology, Schafer and some of the WSP team (which would eventually grow to include the excellent soundwalk artist and acoustic ecologist Hildegard Westerkamp and granular synthesis expert Barry Truax) began capturing sounds. These would provide Schafer with examples of ‘good’ and ‘bad’ urban acoustic design, but also served to build an archive of sounds. The group would typically capture long uninterrupted takes of ambient noise, bells, ships, and mechanical and industrial sounds, including even the sounds of the recordist themselves – footsteps, pants shuffling, breathing.

Left side, a man stands recording near an elephant, right hand side, four white men stand on the steps of Simon Fraser Univeristy.
Image courtesy of http://toysandtechniques.blogspot.ca/2010/12./r-murray-schafer.html

There have been several critiques of the WSP, from Andra McCartney’s troubling of Schafer’s notion of ‘good’ hifi sounds of quiet and nature and ‘bad’ harsh lofi sounds of the city, to Mitchell Akiyama’s analysis of the WSP’s ten-hour piece Soundscapes of Canada and the critical exclusion of non-European voices in the creation of that sonic narrative. However, there’s a nostalgia implicit in the WSP project that is inescapable. And possibly pieces of that same nostalgia is also woven through this Solari project, a longing for the analog past.

This week, we wanted to see how easy it would be to switch the (very heavy) steel supports of the units. They’re currently set up to extend out from the top of the units, and hung from the ceilings when they were installed in Mirabel. We’re planning on rearranging them so they rest on the floor. Hence, we needed to flip the legs around. We were able to get the yellow front façade off with a little bit of work. The six screws holding each fiberglass side panel onto the steel framework require an unusually large squarehead bit to remove, and though we tried a number of bits, we weren’t able to find one big enough. We settled on using a flathead on an angle, and were able to at least get the top façade off. Matt and I then undid the eight heavy bolts attaching the legs to the unit using a ratchet and adjustable wrench. Those came off with little trouble.

Picture showing the metal framework (with four spots for lightbulbs) of the display and the wire patch panel, with the large yellow rectangle of the fibreglass back panel façade at the bottom.

When we took the guts of the unit out to see what we were working with and set it too the one side, we both exclaimed at how lovely it was. “Yeah, what is it about them, that we find so beautiful?” Matt asked, “Is it the bright yellow and black and the crisp whiteness of the text? Or the simplicity, and how carefully done the old design is?” When I first saw a Solari Board, it was in a train station in Germany. I did feel something, some sort of delight. Standing in the station, hearing the cascade of white letters spilling down the blackness of the board. There’s something exciting about it. Maybe it’s the sound of it, the crisp clacking of the splitflaps as they cycle through options. Maybe it’s the action, the rush of analog movement stirring that doesn’t feel the same as a digital sign. But there’s maybe also something to be said about the act of preserving, too. In choosing to take care of something – to record it, to restore it, to activate it – you make it specific. It is not only a matter of having that thing, but also giving it value. It becomes a shared experience, the tug on a sleeve: Do you see this? Did you hear that? Isn’t it incredible?

We’re still on the hunt for the appropriate screwdriver. But it looks like the legs should turn around just fine, and the unit is fitting neatly even when flipped (which means that the bolt distance is the same from the top and the bottom when turned around.

Functioning Unit

This week Mark was able to get one of the Solari units working, using basic keyboard commands. For obvious reasons this is a major step in terms of progress, not least because it’s probably the first time any of the Mirabel Solari units have actually run since the passenger terminal closed in 2004. And it’s certainly the first time any of the MSP’s units have worked since the initial acquisition in 2014.

In order to give us maximum flexibility in terms of display, Mark has figured out how to ensure that we can control the following parameters:

– Flapping speed
– Going directly to the next letter/number or to a blank first
– Setting one letter/number at a time, or the whole row at once
– Remaining stationary if the next letter/number is the same

This will have a direct effect on how expressive the displays can be. (In usability terms, it improves their affordances.)

Meanwhile, Danica and Matt are working on replacements for a few missing split-flaps. It’s amazing what you can find in a local stationery store in terms of raw materials. 🙂

Starting work on the control system

I’m delighted to announce that we’ve hired Mark Demers from Spikenzie Labs in Montreal to work on the control system for the two Solari units. Mark really ‘gets’ the project, and is full of ideas for how we might proceed. He’s also sensitive to the particular technical and creative constraints we’re facing. This includes our wish to avoid making any irreversible physical changes to the Solaris. For example, if at all possible we will use the existing cavities inside the signs to install the new electronics, while bypassing (rather than removing or destroying) the existing components. With proper documentation it should be possible to return the signs to the condition in which they were originally received from ADM, should we eventually want to do so.

In the spirit of openness that has come to characterize the best of the maker community, Mark and I will be sharing our process with the readers of this blog. This will include insights into R&D, prototyping models, and schematics.

Mark_1Right off the bat, then, here’s Mark’s first physical experiment. He says: “I made a mechanical model of the split-flap counter and zero sensor with our laser cutter and I’ve been using it to start working on the coding. It has a DC motor, micro-switches and rotation is controlled by the circuit. It is based on 40 transitions per zero trigger. (Similar to the ones in your sign which have 4 motor rotations with 10 transitions for a total of 40 transitions to sense per full set of flips.)”

What he’s tackling here is the technical specifications of the Solaris, in lieu of any documentation; historically, the Solari factory has not been particularly helpful to folks wanting to get their old signs working again. A major concern of mine is to try to reproduce the original behaviours of the Solari signs: how fast should they flip; in what sequence and direction; individually or all at once? (And what will our artist want them to do?)

Clues can be found online, since a few YouTube users have actually taken the trouble to record Solari boards in action around the world. I thought this video was interesting. The whole row starts changing, but they go straight to the next character without ‘zeroing out’ first (as we had initially thought – wrongly). For example, in the last (white) line, the word ‘KEYSTONE’ becomes ‘REGIONAL’ but the first E doesn’t move at all because it’s already at the right point in its cycle, ie KEYSTONE to REGIONAL. By contrast the ‘logic’ of this homemade one seems all wrong, and rather too fast. This one seems better but weirdly speeds up towards the end of its cycle. And to my mind this is absolutely, completely wrong.

Meanwhile, back to Mark: “I built a new model after seeing the actual display that you dropped off. The new one incorporates gearing and two different plains and rotational speeds for the counter and zero position sensor. I have also included diodes in the same arrangement, so that I could be sure that my counting circuits works with the actual displays….By adding the diodes I had to reverse the polarity of my de-bouncing circuit. There is also a bit more noise since part of the counting circuit is shared with the zero sensor, but I’m currently working though that. The code is at a point where I can type a character and the display updates to that character by first passing through blank.” (April 29, 2016)
“Here is the decoding of the Solari switches.”

Mark_3Finally, for this omnibus update, I’m delighted to welcome Danica Evering to the project. Danica is an artist, curator, and grad student in my department at Concordia. She will be primarily responsible for logistical issues relating to our artist collaborator and the galleries we’ll be working with on the installation.

More updates as they happen.

Initial Breakdown – February 2016


Both displays are extremely heavy: it takes four people and a dolly to move them comfortably. They were suspended from the ceiling at their respective gates in the airport; each one has a pair of vertical, tubular stanchions with threaded ends. Fortunately when we picked them up they all still had washers and nuts.

The fascias are comprised of many smaller sections of black paneling that clip into place, presumably for ease of access and servicing. When removed, these reveal several compartments: a small section, bottom left, with four bulbs to backlight the gate number, plus space for the wiring loom, 3-4 PCBs, and eight Solaris. Don’s initial assessment is that everything was based on contemporary telephone technology. The Solari units can easily be removed by hand, one by one; on the reverse they have one six-pin plug and a longer pin for safe alignment.

The fibreglass yellow ‘jackets’ are purely decorative, and can be removed in two halves (front and back) via screws at the sides. They both show signs of wear-and-tear, particularly some streaks of latex paint on the top edges.

Our current goals:

– confirm that the system is AC (seems some European models are DC);

– complete the inventory of flaps (on the units I’ve checked, a few flaps are missing);

– develop and install a control system for each set of Solaris;

– design a ‘front end’ to allow interaction with the Solaris from a remote device, using ethernet, wifi, and/or Bluetooth;

– figure out better stability, and options for shipping.

More soon….

All about Flight YMX

Mirabel_GateIn October 2014 and February 2016 I acquired two very large ‘Solari boards’ (aka ‘split-flap’ information displays) from the soon-to-be demolished Montréal-Mirabel International Airport passenger terminal (IATA code YMX), courtesy of Aéroports de Montréal. As part of the ongoing Montreal Signs Project at Concordia University, the signs will soon become operational again, using one or more microcontrollers (eg Arduinos).

Solari3I will be working with a Québecois/e poet or electronic literature artist to develop and perform a new work conceived specifically for the displays. The art installation will explore issues relating to migration, modernity, time, mass transit, and ‘liminality’, ie airport departure gates as ‘edge’ spaces that are neither ‘here’ nor ‘there’. By cueing up coded, allusive phrases, flight codes, and times, and having them run cyclically, the installation will thereby put users (‘travelers’) in direct ‘conversation’ with a residual sign technology that is generally associated with anonymous, hidden control centres. The signs will also be Internet-enabled, so we can text or Tweet to the displays remotely – thereby teasing apart the relationships between anonymity, authority, and authorship, via social media.