Because the Free-Form Construction using Grammar is quite a complex topic, we limit ourselves to the simple techniques.
The picture above is of a park constructed between blocks of flats in Manhattan.
Construction process is proposed to proceed by first scattering circles within the region with the specified radius that should not come in contact with one another or the boundary.
Afterwards we grow the regions starting from the circle centre points, resulting in Voronoi regions.
The resulting boundary can be varied by offsetting it with random values along the averaged normal.
Individual regions are contracted and smoothed out. The space between the regions is the path. Separated regions are populated previously described techniques.
Rule Example:
- Region -> VoronoiSmoothed(CircleRegions) { SmoothRegions } { Path }
- CircleRegions -> ScatterCircles(5 {[5-10]})