Classification of fold interference patterns: a reexamination

A modification of Ramsay's (1967) classification of fold interference patterns is proposed, based upon angular parameters in part different from those used by Ramsay. We use the angle between the axes of the first folds and the pole to the axial planes of the second folds as one of our parameters (gamma). Use of this angle plus beta, one of Ramsay's angles, provides a more natural basis for classification of three-dimensional patterns and in particular avoids several ambiguities in Ramsay's scheme.