I am just going to suggest that you do NOT do Cathedral Windows. I realize that you aren't going to use it much - but so much work will go into something that would be distorted almost immediately. I imagine that if you were doing Pineapple blocks, and you pieced them on a fabric background (like paper piecing), it would be gorgeous. While recovering things you need to stretch them tight for a good fit and that would give stability to your piecing. Black and whites? Oh fabulous!