Glass-fin systems are quite simple in concept, utilizing a glass fin set perpendicular to the glass pane at each vertical line of the glass grid. The most challenging aspect of a glass-fin wall occurs when the span is too great to be accommodated by a single piece fin, and a splice detail must be developed to create a fin comprised of multiple glass pieces. Early systems used patch plates to fix the glass and fins together. Spider fittings are frequently used in this application today.