Case study · Cremagencia for Las Lomas · Expocruz 2026

La Torre de Todos

One stand, ten nights, an 1889 portrait on screen in about 20 seconds. 870 visitor portraits, none lost to a system failure. How it was built, what broke, and what we changed.

870visitor portraits in ten nights
1,465faces in those portraits
407group portraits, 2 to 4 people
21 sphoto to TV, median
32 sphoto to a working link on the phone, median
0portraits lost to system failures

The brief

Every visitor, an ironworker of 1889

Las Lomas, a Bolivian steelmaker, brought a stand themed on the Eiffel Tower to Expocruz 2026; the theme came from their brief. We proposed that every visitor see themselves as an 1889 ironworker building the tower, and that all the portraits together form the tower in an online mural. It ran from 18 to 27 September, 20:00 to 23:00.

What a visitor saw

A photo, a countdown, and 1889 on the screen

This is the stand as it ran from the 23rd. The visitor stands on a mark on the floor. Countdown, photo. While the portrait is being made, a line of text warns that it won't be identical: it is a version of them as they would have looked in 1889, in Paris, forging the tower. About 20 seconds later the portrait is on the TV, large, with a code and a QR. At about 32 seconds the link works on their phone. Up to four people fit in one portrait. The operator uses two buttons on a remote.

Ernesto Anaya, a plain test photo
The photo
The same face as an ironworker in 1889 Paris, the tower behind him
The portrait
Another 1889 portrait of the same face, among the tower's girders
Another take, with suspenders and the city behind
Another take, inside the ironwork

The only face on this page belongs to the person who built the Torre: Ernesto Anaya, in team tests. Visitor portraits were made for the online mural, not for advertising, so none are shown here.

The system

Rent by the hour what isn't worth buying

A USB camera. A 2017 MacBook that receives the photo and finishes the portrait. A GPU server rented by the hour in Europe, which does the AI part. A page on dearborn-ventures.com for every portrait, online until 31 October 2026.

The plan was to buy a machine for the stand so nothing depended on the internet. On 17 September, the day before opening, we decided not to buy it. Each visitor uses under 2 MB, so the stand's satellite connection was enough to rent a more powerful server by the hour. When the fair closed there was no hardware left to sell.

The trade-off: no internet, no new portraits. So the decision that mattered most was this one: every photo is saved on the Mac first, and if the server does not answer, it waits in a queue and goes through on its own when the connection returns.

What we measured

Counted from the Torre's own records, twice

Portraits per night. On the first night the server was not available until 22:26.

  • 870 visitor portraits in ten nights. 407 were group portraits of 2 to 4 people.
  • 1,465 faces in those portraits. Someone photographed twice counts twice.
  • 0 portraits lost to system failures.
  • Photo to TV: 21 seconds, median.
  • Photo to a working link on the phone: 32 seconds, median.
  • After the fix on Thursday 24, no photo taken between 20:00 and 23:00 took more than a minute to reach the phone.

Where the limit is. With a line, 66 seconds pass between one photo and the next. The server works for about 20 of them; the rest is countdown, portrait on screen and the next visitor stepping in. The server was busy 16% of the time on average, 44% in the busiest hour. At that pace the stand makes 55 to 60 portraits an hour; the best hour had 58. Serving more people means shortening the cycle at the stand, not renting a bigger server.

Four failures that changed the design

A chain of parts with no spares

From the 18th to the 21st, a different link broke almost every night.

18 and 20 September

The server that vanished

On the first afternoon the rented server disappeared, and that night produced almost no portraits. On Sunday the 20th it happened again, through our own mistake: the prepaid balance ran out and the provider shut the server down.

→ The balance is checked before every night. From the 20th, one server ran without replacement to the end.

Monday 21

The full disk

We launched group portraits that same afternoon, on a busy night. The server's disk filled up, and from 22:25 the internet was down. 29 portraits arrived between 1 and 3.6 hours late. None was lost.

→ From the 23rd, an automatic watchdog checks everything every five minutes and keeps the disk clean.

Wednesday 23

The screen that froze

The TV froze for a few seconds during every portrait. The program on the Mac waited for the server and answered nothing else meanwhile.

→ The heavy work now runs separately. On a test copy, during a portrait, the Mac went from taking 22 seconds to answer to taking 5 milliseconds.

Friday 25 and Sunday 27

The cut at closing

The internet went off at closing time with photos still queued. The queue held every one, and they went out on their own when the connection returned, the last one 1 hour 45 minutes later.

→ New step in the closing guide: the night isn't over until the last portrait is on the TV.

What prevented losses was a design decision: the queue. Without it, the photos taken during the outages on the 21st, 25th and 27th would have been lost.

What we would do differently

Three changes for the next event

Measure whether people kept their portrait

We know how many portraits went out, not how many were opened or shared.

Treat the internet and the computer as critical parts

The connection caused the longest waits and was never measured; the Mac restarted at 20:13 on the last Sunday, with the stand open. Next time: a measured connection, a newer computer, a UPS.

More time, bigger type

The QR stays 20 seconds, in small type; many older visitors struggle to scan it in time. What worked best: someone at the stand photographing the screen with the visitor's phone.

The same discipline, at a live event

Built by Cremagencia, the agency arm of Dearborn

Dearborn runs as one system: a building administration platform, a laundry vertical under construction on the same rails, and an agency that brings in cash for the rest. The Torre was built by Cremagencia, the agency arm.

Same method as the rest: measure before changing anything, rent by the hour what isn't worth buying, own the code and the domain, and write each failure down where the next person will find it. The machine is meant to be set up at another event, with another brand and portrait style; it hasn't run outside this fair yet. In design, not built yet: a self-service kiosk with no Mac at the stand.