Often I find a tie or group of ties that suggest a project.  In September's "High Tied", I used several ties that were in a bag given to me.  In looking through the bag, I found a wild pattern that suggested water.  Further searching yielded more blues and 2 or 3 sandy-colored ties or scraps.  I used most of the wide end of the wild tie and used a sew-and-flip method to add strips and chunks of blues and sands to fill an approximately 20" square.  Because I didn't interface the ties, the fabrics shifted as needed to accommodate curvy piecing.