This cocktail dress, from Butterick 5779, is made of silk dupioni and it includes an eye-catching lace back panel. In Threads #209 (June/July 2020), author Andrea Schewe shares her method for inserting a discreet invisible zipper. Andrea demonstrates how strips of silk dyed to match the wearer's skin tone conceal the seam allowances and zipper tape. She also explains how to cut the left and right back panels so the lace motifs are mirrored perfectly . Andrea shortened the dress from floor-length with a short train to cocktail length. The pattern includes a full-length view with a longer train and long sleeves.