Много, много объектов

function Circle (width, height) {
    this._width = width;
    this._height = height;
    this._htmlItem = false;
}
Circle.prototype.constructor = new Circle();
 
Circle.prototype.createOne = function(whereAppend){
    this._htmlItem = document.createElement("div");
    this._htmlItem.style.width = this._width + "px";
    this._htmlItem.style.height = this._height + "px";
    this._htmlItem.style.borderRadius = "50px";
    this._htmlItem.style.backgroundColor = "red";
    this._htmlItem.classList.add("circle");
 
    this.appendToHtml(whereAppend);
}
Circle.prototype.appendToHtml = function (selector) {
    var whereAppend = document.querySelector(selector);
    whereAppend.appendChild(this._htmlItem);
}
Circle.prototype.addEvent = function (evName, fn) {
    this._htmlItem.addEventListener(evName, fn);
}
 
for (var i = 0; i < 1000; i++) {
    var circ = new Circle(100, 100);
    circ.createOne(".elems");
    circ.addEvent("click", function () {
        alert("clicked");
    })
}

function Figure(options) {
    this.figure = options.figure || "square";
    this.width = options.width || 100;
    this.height = options.height || 100;
    this.htmlItem = false;
}
Figure.prototype = Object.create(Figure);
 
Figure.prototype._isCircle = function() {
 
    return this.figure === "circle" ? true : false;
};
 
Figure.prototype.createOne = function(whereAppend){
    this.htmlItem = document.createElement("div");
 
    if (this._isCircle()) {
        this.htmlItem.style.borderRadius = "50%";
        this.htmlItem.classList.add("circle");
    } else {
        this.htmlItem.classList.add("square");
    }
 
    this.htmlItem.style.width = this.width + "px";
    this.htmlItem.style.height = this.height + "px";
    this.htmlItem.style.backgroundColor = "red";
 
 
    this.appendToHtml(whereAppend);
}
Figure.prototype.appendToHtml = function (selector) {
    var whereAppend = document.querySelector(selector);
    whereAppend.appendChild(this.htmlItem);
}
Figure.prototype.addEvent = function (evName, fn) {
    this.htmlItem.addEventListener(evName, fn);
}
 
for (var i = 0; i < 100; i++) {
    if (i % 2 === 1) {
        circ = new Figure({figure: "circle", width:200, height:200});
        circ.createOne(".elems");
        circ.addEvent("click", function () {
            alert("clicked on circle");
        });
    } else {
        square = new Figure({figure: "square", width:200, height:200});
        square.createOne(".elems");
        square.addEvent("click", function () {
            alert("clicked on square");
        });
    }
};

 this.htmlItem.style.display = "inline-block";