The Banque de Newport series presents Newport scenes as a series of bank notes. In these works the smooth curves and repeating background patterns are wave scans. Wave scans are created by assembling a sequence of scan lines from the frames of video footage into a single image. For example, the waves in Easton's Bay on the 500 Coquilles (shells) note look odd because each wave is seen earlier on the right side of the image and later on the left side.

The wave scans in these images are a form of naturally occuring guilloché patterns.

Guilloché (Guilloche) is a decorative engraving technique in which a very precise intricate repetitive pattern or design is mechanically engraved into an underlying material with fine detail. - see the full Wikipedia article on Guilloché

see also The Ministry of Type, a weblog by Aegir Hallmundur, about type, typography, lettering, calligraphy and other related things.