to the first pitch by step. Often representative of the Christian cross, such melodies are cruciform in their retrogrades or inversions. Johann Sebastian Bach, whose last name may be represented in tones through a musical cryptogram known as the BACH motif that is a cruciform melody, employed the device extensively. The subject of the fugue in c-sharp minor from The Well-Tempered Clavier Book I is cruciform. See also: Cross motif. Cruciform tail Some airplanes use a cruciform tail design, wherein the horizontal stabilizer is positioned midway up the vertical stabilizer, forming a cruciform shape when viewed from the front or rear. Some examples are the F-9 Cougar, the F-10 Skyknight and the Sud Aviation Caravelle. The cruciform tail gives the benefit of clearing the aerodynamics of the tail away from the wake of the engine, while not requiring the same amount of strengthening of the vertical tail section in comparison with a T-tail design. Cruciform sword The plain sword used by knights, distinctive due to the flat bar used as a guard. The overall shape of the sword when held point down is that of a cross. It is believed this shape was encouraged by the church to remind Knights of their religion. It was however very popular due to the protection it offered to the hand and certain attacks that rely on the cross to trap the blade of the enemy. See Sword. Cruciform web design Cruciform web designs use a cross-shaped web page that expands to fill the width and height of the web browser window. There are a number of different approaches to implementing them. Cruciform product design In addition to common cross-shaped products, such as key chains and magnets, certain designers have gone so far as to create cruciform devices and accessories. For example, the mass-produced cruciform MP3 player "Saint B", or the "iBelieve", an accessory that converts the original iPod Shuffle into a cross shape designed by Scott Wilson in 2005. The cruciform MP3 players often come preloaded with audio files of the New Testament, but are mainly purchased for users to proudly display their faith. See also Crucifix References Church architecture