public class Triangle {
    public double base;              // instance variable
    public double height;            // instance variable
    public String color;             // instance variable
    public static int numSides = 3;  // static variable

    public Triangle(double base, double height, String color) {
        // base, height, and color are "local" to the Triangle constructor method
        // this.base, this.height, this.color belong to the Triangle instance
        this.base = base;
        this.height = height;
        this.color = color;
    }

    public double area() {
        return 0.5 * base * height;
    }

    // this is a static method!
    public static int sides() {
        // numSides is a static variable, meaning that it is
        // stored in the class (not in an instance!)
        return numSides;
    }

    public static void main(String[] args) {
        // we can call static methods and access static data without
        // having an instance of Triangle!
        System.out.println("Your triangle has " + Triangle.sides() + " sides.");

        // base, height, and color are local to main
        // yes, these are DIFFERENT variables than the ones with the same
        // name stored in the instance or local to the Triangle constructor
        double base = Double.valueOf(args[0]);
        double height = Double.valueOf(args[1]);
        String color = args[2];

        // now we finally make an instance (object) of Triangle
        Triangle t = new Triangle(base, height, color);
        System.out.println("Your " + t.color + " triangle has area: " + t.area());

        // And look, we can even access static data THROUGH a reference to
        // a specific object. Take a moment and ask yourself why this is always OK.
        System.out.println("Your triangle still has " + t.sides() + " sides.");
    }
}