I need to carpet a riser(4'X6', 12" tall) and a step(6'X6" tall) and I need some advice. How do I tackle the outside corners? I'm thinking of using an indoor/outdoor carpet I saw at Home Depot. The room is already carpeted and the riser will just sit on top of carpet, with the step secured to riser. Does anyone have any photos showing the corner method, or know of any links? Thanks.