"Horseshoe" is the name of the main song the Paoli 1 Drum and Bugle Corps plays. It is based off of the cadence played during Retreat at Horseshoe and should not be confused with the camp song, In the Loop of the Octoraro Bend. Over the years scouts have made slight changes and modifications to the song but it remains true to its origins. Technically "Horseshoe" only refers to the introductory part which resembles the cadence played by its namesake, but that name has come to describe all four sections of the song.
The song is structured into four parts, two "drum solo" sections and two bugle sections with accompanying drums. The sequence is started by four loud base drum beats. The entire song as well as those four beats are played at the same tempo of the marching cadence (thus a scout's left foot should hit the ground in time with the bass drum's downbeat and the right foot should hit on the upbeat).
To make the bare backbone of "Horseshoe" the Drum and Bugle Corps needs three instruments. Without any of these three instruments the whole song cannot be played.
The Bass Drum - It is needed to signal the introduction of the song and to keep the beat throughout. The drummer is usually an older and stronger scout who can carry the drum for long periods of time such as during the three mile long Memorial Day Parade. The beat is also essential for marching scout to stay in step, which means the drummer must be rhythmically talented and have the endurance to play steadily for the entire march.
The Snare Drum - This instrument provides the other beats to fill the main portions of Horseshoe and also to support the bugle section of the song. The snare rhythms are more complex than the bass drum so it is usually for more experienced and skilled drummers to play.
The Bugle - The only wind blowing instrument (although it is a brass instrument), the bugle is required for the two calls within the song (although it does not play for the introductory piece or the 'drum solo' part,). Any scout with a background in brass instruments can play the bugle which only has four tones changed by tonguing.
Not only can there be multiple snares and bugles (there should only be one bass drum) there can also be other instruments that complement the song.
The Tri-Tom - This instrument provides a source of rhythm and other tones to make the drumming sound more full.
The Tom-Tom - These basic drums provide another beat to support the snare. They can do complex rhythms or simple ones such as following the bass drum. The choice is up to the Captain's discretion.
Buglers can also be supported with a trumpet, but rarely has this ever been done for anything but the bugle call.