Oi Vai is slang for Dear Me! Its an expression of surprise (or dismay) or delight (or hurt): like what happens when you listen to this song.
The piece has a single melodic theme
Offsetting the starting note of the theme backwards and forwards in time creates lots of melodic variations. The variants are played by different instruments to create new harmonies and rhythms.
The theme is a short melody based on a pentatonic scale.
The five notes in the scale are 0, 4, 5, 9 and 10. In the key of B, these are the notes B, D#, E, G# and A . This pentatonic scale has been used many times before in many different ways. Ian Carr's Nucleus did a good version on their 1970s album, Elastic Rock, interpreting it as a Balinese scale.
The first variant plays the theme then repeats it and offsets the first note forward by half a beat.
The second variant starts on the third beat of the second bar of the first variant.
The third variant starts on the second offbeat of the first bar of the first variant.
Offsetting always produces something unexpected. Often it is a surprising harmony, other times it is an arresting rhythm, such as variant X, starting on the sixth eighth-beat of the first variant.
Oi Vai indeed!
Title: Oi Vai
Length: 3' 15"
Track 1: muted guitar
Track 2: steel guitar
Track 3: fretless bass
Track 4: drumset
Genre: pop, rock