OK, hold on a second here. It’s sort of Foundation String piecing, but not really. Foundation string piecing is using a square of paper (which you later remove) or fabric (which becomes part of the quilt) and sewing strips of fabric to cover the ENTIRE size of the foundation. You then trim it to the size block you want.
https://www.youtube.com/watch?v=iZ02NM9-USw
You’re showing something where you don’t cover the entire foundation. Is there a picture of the finished block?