Fabric.js geometric shapes

I want to use different geometric shapes (like hexagon, star...) apart from Rect, Triangle, Ellipse.What else can I do? How can I do?

var canvas = new fabric.Canvas('c');
var rect = new fabric.Rect({
  left: 50,
  top: 50,
  fill: 'green',
  width: 40,
  height: 80
});
var circle = new fabric.Circle({
  radius: 20, 
  fill: 'red', 
  left: 100, 
  top: 100
});