not become involved with field marching, and vice versa. Various venues exist for street marching competitions between high school marching bands. Field marching While playing music during a field show, the band makes a series of formations, called drill, on the field, which may be pictures, geometric shapes, curvilinear designs, or blocks of musicians, although sometimes it may be pure abstract designs using no specific form. Typically, each band member has an assigned position in each formation. In many show bands and most drum corps, these positions are illustrated in a handheld booklet called a drill book (also known as a dot book). Drill books, or drill charts, show where each person stands during each set of the show. The drill charts include yard lines and hashes as they would be on an actual football field, which shows the band members where to stand relative to the yard lines and hashes. There are many ways of getting from one formation to the next: Each member moves independently called scattering or scatter drill. All members move together without deforming the formation—called floating. Members stay in their lines and arcs, but slowly deform the formation—sometimes called rotating, expanding, or condensing. Members break into ranks or squads, each of which performs a maneuver (such as a follow-the-leader) which may or may not be scripted. An unscripted move is sometimes called a rank option. Each member performs a specifically scripted move. In these cases, the desired visual effect is often the move itself and not the ending formation. Members at an extended halt perform a stationary visual move, such as a ripple (like "the wave") or some sort of choreography, that may propagate throughout the formation of band members. Players may point the bells of their instruments in the direction they are moving, or slide (also called traverse) with all the bells facing in the same direction. They may also point it towards the center of the field. Bands that march in time with the music typically also synchronize the direction of individuals' turns and try to maintain even spacing between individuals in formations (called intervals). Sometimes bands specifically have wind players turn their instruments away from the audience to emphasize the dynamics of the music. Auxiliaries can also add to the visual effect. Backdrops and props (scrims) may be used on the field that fit the theme of the show or the music