Either paint the back of the repurposed glass pane door or staple gun a nice run of cool print fabric for this great focal point for pennies. --- i'd use it as a custom fence gate. Check out the selection at Antiques and More at Staley Road Champaign Il.
How to make a mosaic mushroom ~ This type was made over a glass bowl (covered in plastic wrap), with the concrete over it. (Hypertufa would be lighter weight) The stem is a bud vase with the concrete mix over it.
Garden Stepping Stones Helpful tip - put a layer of damp sand in the bottom and then nestle in your mosaic elements. The sand will help keep the elements in place when you add the concrete, and it gives the top of the stone a textured look.