Fractional Angle Networking
From SC4 Encyclopaedia

Fractional Angle Networking is an effort by several NAM Team members to break road and rail networks out of the orthogonal/diagonal grid. The road side of the project is called the FAR (Fractional Angle Roads) and the rail side, not surprisingly, is called the FARR (Fractional Angle Railroads). The reason these pieces are called "fractional angle" curves is because, even though they are neither orthogonal nor diagonal, they are still constrained by SC4's grid, albeit the additional angle variety loosens the impositions that the grid places on network placement. There are currently two different fractional angles employed: FA3 (18.4/71.6 degrees), and more recently, FA2 (26.6/63.4 degrees). They are named with respect to how they lay on the SC4 grid: FA3 is named such because it requires 3 tiles on the xaxis to move 1 tile on the yaxis, and for FA2, the figures are 2 tiles on the xaxis for 1 tile on the yaxis. Other proposed angles have included FA4, FA6, and FA1.5, though there is no concrete plan with respect to their implementation at present.
The concept originated in the early spring of 2008 with a post in Three Rivers Region (3RR) by David (dedgren) proposing the FAR and developing a set of texturebased road curves . Within a short time, dedgren and Tarkus, who had worked together the previous year on a similar project that became the NAM wide curves, had a working set of FAR pieces. In the early summer of 2008, dedgren expanded the concept to dualrail, and once again he and Tarkus collaborated on creating the initial set of FARR pieces. Shadow Assassin later expanded the fractional angle options to include the RealHighway system (FARHW), with the release of RealHighway Version 4.0 in May 2010 (coincident with NAM 28), and later, he developed Fractional Angle Avenues.
The biggest development with respect to fractional angles came with memo's development of Draggable Fractional Angle Networking, which uses INRUL and RUL2 code to transform draggable patterns into fractional angled networks. As of the NAM 31.xseries releases, the draggable approach is currently only available for Roads, in both FA3 and FA2 angles.