Place waxed paper onto trays. Melt chocolate and then pour tempered chocolate into a metal bowl. Dip Oreo cookie's in chocolate. Make sure to completely immerse the cookies in chocolate, or they will go stale quickly. Place chocolate covered cookies onto waxed paper. Swirl the tops of each cookie with a different color of melted chocolate. Add sugar decorations, which can be bought in baking supply store. Refrigerate for at least 15 minutes, or until hard to the touch.