Using a combination of traditional devices and layout mode shapes as masks, you can put these anywhere you like on the terrain. You can arbitrarily vary the angles and shape/ area of the incline.
http://www.skindustry.net/medem/files/Phase2/Terrain_1.0/screenies/160308/3D%20View01.png
http://www.skindustry.net/medem/files/Phase2/Terrain_1.0/screenies/160308/3D%20View02.png
monks