Paper.JS effect stack prototype

paperjs-fx-stack.js

function roughenSegments(path,amp){
    var amp=amp || 10;
    for(s in path.segments){
        var seg=path.segments[s];
        seg.point.x+=Math.random()*(2-1)*amp
        seg.point.y+=Math.random()*(2-1)*amp
    }
}

Item.prototype.roughen = function (amp) {
    var amp=amp || 10;
    var self=this;
    var itemTypes={
        Path(){
            roughenSegments(self,amp)
        },
        CompoundPath(){
        },
        Shape(){
        },
        Raster(){
        },
        SymbolItem(){
        },
        PointText(){
        },
        Group(){
            for(var i in self.children){
                var item=self.children[i];
                roughenSegments(item,10)
            }
        },
        Layer(){
        }
    }
    itemTypes[this.className]()
    return self
}

Item.prototype.repeat = function (options) {
    var pt=options.offset || new Point(10,0);
    var num=options.copies || 5;
    var self=this;
    var itemTypes={
        Path(){
            var group=new Group();
            group.appendTop(self)
            for(var i=0;i<num+1;i++){
                var clone=self.clone()
                clone.position+=pt*(i+1);
            }
            self=group;
        },
        CompoundPath(){
        },
        Shape(){
        },
        Raster(){
        },
        SymbolItem(){
        },
        PointText(){
        },
        Group(){
            var group=new Group();
            group.appendTop(self)
            for(var i=0;i<num+1;i++){
                var clone=self.clone()
                clone.position+=pt*(i+1);
            }
            self=group;         
        },
        Layer(){
        }
    }
    itemTypes[this.className]()
    return self
}

Item.prototype.scatter = function (radius) {
    var radius=radius || 10;
    var self=this;
    var itemTypes={
        Path(){
            self.position+=Math.random()*radius-(radius/2)
        },
        Group(){
            for(var i in self.children){
                self.children[i].position+=Math.random()*radius-(radius/2)     
            }
        },
    }
    itemTypes[this.className]()
    return self
}

Item.prototype.colorize = function (color) {
    var color=color || new RGBColor(1,0,0);

    var self=this;
    var itemTypes={
        Path(){
        },
        CompoundPath(){
        },
        Shape(){
        },
        Raster(){
        },
        SymbolItem(){
        },
        PointText(){
        },
        Group(){
            for(i in self.children){
                var item=self.children[i];
                item.fillColor=new Color(
                    Math.random(),
                    Math.random(),
                    Math.random())
            }
        },
        Layer(){
        }
    }
    itemTypes[this.className]()
    return self
}

var path=new Path.Rectangle({
    position:[100,100],
    size:[10,50],
    fillColor:"blue"
})


path
.repeat({offset:new Point(10,0),copies:40})
.roughen(40)
.colorize("red","blue")
.scatter(150)



console.log(project.activeLayer.children)