JSFiddle - React, Tailwind, and code Playground

HTML

<style>
    html, body {
        width: 100%;
        height: 100%;
        font-family:'Lucida Console';
        background: #575757;
        color: white;
        margin: 0px;
        overflow-y: hidden;
    }
    #console {
        width: 95%;
        height:90%;
        padding: 10px;
        overflow-y: auto;
    }
    #console div {
        margin-top: 5px;
    }
</style>
<div id="console"></div>
<script>
    var panel = document.querySelector("#console");
    var print = function(m) {
        var newline = document.createElement("div");
        newline.innerHTML = "&gt; " + JSON.stringify(m);
        this.panel.appendChild(newline);
    };
</script>

JavaScript

function Animal() {}

function Bird() {}
Bird.prototype.__proto__ = Animal.prototype;

var animal = new Animal();

// how deep
print(animal.__proto__.__proto__.__proto__);

// tests
print(animal.__proto__ == Animal.prototype
    || animal.__proto__.__proto__ == Animal.prototype);
print(animal.__proto__ == Bird.prototype
    || animal.__proto__.__proto__ == Bird.prototype);