Casablanca stencil by Cutting Edge Stencils on Etsy. They have a great video tutorial. Basically all you do is tape up the stencil (I’ve heard spray adhesive works well too) then load up your roller, dab off the excess on a paper towel and roll away. Then you overlap the stencil as you move along. For this wall I color matched a robins egg blue with Gliddens Briliance Paint from Walmart.