Layer flannel and fusible webbing squares. Arrange ribbons on the fusible webbing side, allowing the top ribbon to extend 1/4 inch beyond the webbing. Following the manufacturer's instructions for the fusible webbing, fuse ribbons to the flannel square.
Machine-stitch the ribbons together along the edges using a variety of decorative stitches. Fold the top ribbon to the back of the square and stitch close to the edge.
Fold the piece with right sides together, aligning the ribbon ends. Sew the long edge and the bottom short edge using a 1/4-inch seam allowance and round the corner. Clip the corner; turn the case right side out.