From ant colonies to honeycombs, natural patterns emerge without blueprints, and human road networks echo that mystery. The author recalls early fascination with SimCity 2000, noting how roads have become the backbone of every city‑building title. Over decades, games added elevation, diagonal and curved segments, yet realism often lagged.

Cities: Skylines broke new ground by allowing free‑placement roads, flyovers, and arbitrary intersection angles, but its highway ramps still appeared unnaturally sharp. Community mods patched many flaws, delivering smooth merge lanes and realistic markings, yet they remained constrained by the engine’s underlying Bezier spline system, which struggles to preserve parallelism on tight curves.

The core issue lies in Bezier mathematics: offsetting a curve does not yield another Bezier, causing inner and outer