Grass Slopes were introduced with Patch R36 on November 15th 2016.
2 of these Slopes can be made in a Processor from one block of green Grass each. No crafting recipe has to be unlocked for that.
Grass is a very common surface block that can be found in many Biomes, such like Grassland, Woodlands, Forests and Swamplands.
Different from cubic blocks of ordinary green Grass, Grass Slopes cannot be corrupted by Corrupt Bombs nor by Corrupted Water.
Grass Slopes will not turn blocks of Dirt into blocks of Grass when placed next to each other.
Dead Grass and Savannah Grass cannot be processed into Grass Slopes.
Since R42 in May 2017, inner and outer corners blocks can be created for Grass Slopes too by putting them into a Processor. No crafting recipes are required for this.