This is a demonstration of a generative study. Its materials are simple: a set of parallel marks, a shared interval, and a region where that interval changes.
The rule and its exception
A uniform field gives the eye an expectation. A small displacement becomes readable because it breaks that expectation. The central fold is made by moving groups of marks in measured steps, allowing a regular rhythm to gather into an irregular volume.
The image is deterministic. The rule produces the same specimen each time, so a changed result can be traced to a changed decision. There is no need for randomness in this particular study; the interesting tension is already present between repetition and interruption.
Keep the quiet parts
Early versions filled the entire plane. Removing marks made the fold easier to see. The open region at the edge now participates in the drawing: it gives the denser center somewhere to release its weight.
The next useful variation would change the interval without changing the overall shape. That would test whether the fold belongs to its silhouette or to the rhythm of its internal marks.