There's a way to make this harder to detect: create "loops" which are actually a multitude of loops that have prime number lengths. The individual components will repeat, but "beats" of simultaneous repeats won't exist, giving the illusion of a much longer sequence.

I've seen an example in graphics used to create very large tiling patterns from a small image space. See:

http://web.archive.org/web/20110410071059/http://designfesti...