Random Population

randomPopulation.js

/**
     * Generate random DNA for the Initial Generation
     * Value Encoding is used for DNA encoding
     * DNA = [RED, GREEN, BLUE, ALPHA, X1, Y1, X2, Y2, ...]
     * */
    randomGenes(){

        var bString = [];
        for (var i = 0; i < this.chromoSize; i+= this.geneSize){
            /**
             * Generate RGBA
             * */
            bString.push(
                Math.random(), // R
                Math.random(), // G
                Math.random(), // B
                Math.max(Math.random() * Math.random(), 0.2) //A
            );

            /**
             * Generate random (x,y) for vertices
             * */
            var X = Math.random();
            var Y = Math.random();

            for (var j = 0; j < this.vertices ; j++){

                bString.push(
                    X + Math.random() - 0.5,
                    Y + Math.random() - 0.5
                );
            }
        }
        this.valueString = bString;
    }

What's going on at line 17 ?