In those pieces, the glitches (literally slippages), were engineered by painting the simplest possible motif, parallel stripes, upon tape wound around a rectangular frame, which was then rewound around another frame with a different (and possibly irregular) width.
This is OK as far as it goes, but it's contrived. The parallel stripes provided, in essence, a regular alternating on & off or 1 & 0 binary data stream which was then slipped against itself by the critical rewinding step. By varying the tension applied to each turn of the winding, the amount of slippage could be finessed.
Therefore, I've been hunting for a natural source of data that has slippages baked-in – but not any sort of slippages – I wanted a mostly regular signal with occasional discontinuities and slowly-evolving frequency drifts.
Can you guess what the data source is? Hint: This piece is named after an actual human being. In fact it's my co-author of Glitch: Designing Imperfection (2009).