Grid

function Block( x, y, w, h, d ) {

	this.x = x;
	this.y = y;
	this.w = w;
	this.h = h;
	this.d = d;

	this.children = [];

}

Block.prototype.split = function() {

	var x = this.x;
	var y = this.y;
	var w = this.w;
	var h = this.h;
	var d = this.d;

	d *= .75 + Math.random() * .5;

	if( Math.random() > .5 ) {
		var hw = w / 2;
		this.children.push( new Block( x, y, hw, h, d ) );
		this.children.push( new Block( x + hw, y, hw, h, d ) );
	} else {
		var hh = h / 2;
		this.children.push( new Block( x, y, w, hh, d ) );
		this.children.push( new Block( x, y + hh, w, hh, d ) );
	}

}

Block.prototype.getUnsplitBlocks = function() {

	if( this.children.length === 0 ) return this;

	var nodes = [];
	this.children.forEach( function( b ) {
		nodes = nodes.concat( b.getUnsplitBlocks() );
	});

	return nodes;

}

var b = new Block( 0, 0, 100, 100, 5 );
b.split();
for( var j = 0; j < 12; j++ ) {
	var nodes = b.getUnsplitBlocks();
	nodes.forEach( function( b ) { b.split() })
}