needed, based on the complexity of the show (in which case, in a three-person scenario, one stands on the 50-yard line while another stands on the 30-yard line and the third stands on the other 30-yard line), and occasionally, additional individuals may be asked to perform brief conducting duties if beneficial in a particularly tricky part of the show (more often, such people are those on the sidelines or in the pit). The modern-day concept of the drum major has been exponentially expanded upon by George N. Parks, often known as the "Dynamic Drum Major," through his Drum Major Academy. Bands may also be led by a more traditional conductor, especially during field shows, where a stationary conductor on a ladder or platform may be visible throughout the performance. Aural commands—such as vocal orders, clapping, or a whistle—may be used to issue commands as well. In show bands, particularly in HBCU and Big Ten bands, drum majors often have a visual on-field role with a baton or mace, with the job of conducting assigned to the band director(s). In these cases, the number of drum majors is often based on tradition, rather than being in proportion with the number of musicians. For example, the Florida A&M Marching 100 fields one drum major for each president in the university's history. Other leaders within the band may include field lieutenants and captains of sections such as brass, drumline, and woodwinds, and members that lead a section, squad, row, etc. Some bands assign drum majors the dual role of leading and conducting the ensemble on the field. This is most common in traditional military-style groups, such as Texas A&M's Fightin' Texas Aggie Band: the drum majors march with the band, sound whistles to coordinate movement, and use maces to keep time by thrusting them up and down (rather than toward and away from the body, as is typical in American military bands). The size of the band may not only determine how many drum majors there are, but how many section instructors are needed as well. Section instructors function like the music director but are mainly responsible for teaching members of a given section. Because they are commonly previous members of the section they teach, they can provide better instruction to combine the needs of the show with the characteristics of the given instrument. As bands require leadership from within as well as