eaglercraft-1.8-workspace/desktopRuntime/resources/assets/minecraft/blockstates/grass.json

{
    "variants": {
        "snowy=false": [
            { "model": "grass_normal" },
            { "model": "grass_normal", "y": 90 },
            { "model": "grass_normal", "y": 180 },
            { "model": "grass_normal", "y": 270 }
        ],
        "snowy=true":  { "model": "grass_snowed" }
    }
}