Onboards Biennale transforms Antwerp’s urban landscape into an interactive exhibition, reimagining billboards as spaces for collective artistic encounters. The 2025 edition centred on the theme of ‘relationships’. The jury of Onboards Biennale 25 selected artist Maarten Inghels for a presentation in INBOX.

Thieves’ Code
A sign system of his own
Since 2024, Maarten Inghels has been marking the pavements of the cities he visits with a sign system of his own making. For each front door, he carefully selects a symbol based on what he can discover about the resident through the window or letterbox. Does someone own a lot of books? Is there a cat sitting on the windowsill? Can he hear a dog? Do posters in the window reveal anything about the resident’s political preferences? Is there a security camera? A garden or swimming pool?

Through this intervention in public space, Inghels investigates and documents the stigmatising term thieves’ code. At the same time, he attempts to make the intimate public. To an outsider, the symbols remain enigmatic, but with the accompanying key, the street becomes readable in a different way. The work invites reflection on fears surrounding migration and the increasing pressure on our privacy.

The myth of the thieves’ code
For years, news outlets across Europe have warned the public to watch out for strange markings on walls, bins, doors and pavements near homes. Circles, lines, squares, wavy marks, crossings-out. These cryptic symbols, often drawn in chalk or sand or made with matches, may appear innocent or insignificant, yet police forces warn that they form part of a thieves’ code used by travelling criminals to exchange information about a property in secret. Various dictionaries translating this thieves’ language circulate online. Secured house. Previously burgled. Good loot. Woman alone. Too risky. Wealthy residents.

There is a historical precedent. Houses were marked centuries ago. Graffiti was used to indicate which households were open to people without a permanent place to stay. This hybrid visual language helped people on the move survive by directing them towards food, drink or shelter. It was a language of the road. Symbols for police, prison and trouble were endlessly copied and adapted. There is, however, no conclusive evidence that itinerant groups still use such codes today. Markings made by utility companies and children continue to fuel the urban legend.

Confusion in Zottegem
When Inghels began working with his chalk in Zottegem, it was not long before the police and mayor issued a news report following several complaints from concerned residents about thieves’ markings in the streets. After a thorough police investigation concluded that the markings were the work of an artist, Maarten Inghels began to feel guilty.

https://www.muhka.be/en/exhibitions/maarten-inghels-thieves-code/

Artists: Maarten Inghels