No pattern. Strips are sewn on the diagonal starting with the center, corner to corner strip long enough to cover the corners of the foundation. After that, it's just adding strips on each side using the sew and flip method until the foundation is covered. Turn the completed block wrong side up, center the diagonal line of a large square ruler between the starting 2 corners and trim excess fabric and foundation to your block size.
I usually cut my blocks about 1/2 in. smaller than original foundation as there is some shrinkage during sewing. I also cut fabric squares, cut them into half sq. triangles and use them to fill the last 2 corners instead of using strips. Quicker and saves fabric in the long run.
Any width strip can be used although the wider the strip, the less interesting the final block will be. Mixing the widths and even using those that are angled or purposely anglling some is fine.
Just go for it and use up those leftovers.
Ellie