objects.js

function Animal() {
	this.eyes = 2;
	this.legs = 4;
	this.name = "Animal";
	this.mutate = function () {
		this.eyes += 1;
		this.legs += 1;
		this.name = this.name + "...";
	};
}

var snake = new Animal();
snake.eyes = 2;
snake.legs = 0;
snake.name = "Snake";
console.log("Here's a snake.");
console.log(snake);

console.log("Let's mutate him!");
snake.mutate();
console.log(snake);