The subject of repitition has brought to mind a song by Kevin Ayres during his 'Kevin Ayres & the Whole World' days.
They did a 'song' comprised of nothing more than a repitition of the title, and the title was 'I Did it Again'.
'I Did it Again' was repeated not so much like a mantra, but as a vocal riff. It was in unison with the bass line (Kevin was a bassist). It was rather more than just some endless riff though, as the the chords would shift underneath it & eventually build to a climax and a cadence, before restarting once more (not unlike computer music 30 years later).
Kevins excellent idea was to turn the song form on its head and have the vocal fill (& support) the role of the bass, and give the harmony (keys) an (almost) leading role.
It has to be one of the most memorable tunes Ive ever heard. I last heard it 30 years ago, and its still fresh in my mind.
A little over half way through, the trance element would kick in (for me anyway) when every time Kevin sang 'I Did it Again' sounded as if he was refering to the last time he sang 'I Did it Again', a cycle of about 1 second continuously updated. Very unusual, highly effective.