queryRange(rangeAABB) {
        var foundballs = [];
        if (!this.boundaryAABB.intersectsAABB(rangeAABB)) {
            return foundballs;
        }
        for (let c of this.balls) {
            if (rangeAABB.containsball(c)) {
                foundballs.push(c);
            }
        }
        if (this.nw == null) {
            return foundballs;
        }
        Array.prototype.push.apply(foundballs, this.nw.queryRange(rangeAABB));
        Array.prototype.push.apply(foundballs, this.ne.queryRange(rangeAABB));
        Array.prototype.push.apply(foundballs, this.sw.queryRange(rangeAABB));
        Array.prototype.push.apply(foundballs, this.se.queryRange(rangeAABB));
        return foundballs;
    }