I filled in with blue iridized glass and colored frit for interest in the background. I used crushed rocks on the sandy beach to fill in and provide texture, then poured / spread four cups of resin over it all. After I spread the resin, I sprinkled some clear glass chips and some additional blue filler around the background. I likely could have used a bit more resin, though this is the most I’ve ever needed for a window. I’m still learning about working with the resin, as this is only my fourth window using it. Approx. 30 5/8″ W x 28″ H.