The Overgrown Style is a graffiti tradition practiced exclusively on structural ferrocrete — the load-bearing pillars, bridge undersides, and retaining walls of GLMZ's Shelf infrastructure — using a technique that embeds living bioluminescent moss culture directly into the tagged surface. Works begin as simple painted stencils but bloom over weeks into three-dimensional luminous growth, making the art literally alive and impossible to remove without structural damage. The movement was pioneered by a loose collective operating under the tag 'FERROVERDE' around the Calumet Flats district, and their flagship piece — a 40-meter pillar mural called the Grandmother Lung — has been growing continuously for nine years. Corporate maintenance crews have twice attempted removal and twice been blocked by Shelf residents who argue demolition would compromise the building's structural integrity.