Pattern mode is a WikiMode that strives to put the page in PatternForm, with optional discussion and supporting evidence below the main document.
Pattern mode can result from ThreadMode; it is the further focusing of the threaded discussion, by definitive descriptions which can elaborate and qualify -- usually in a factual manner -- the ideas and thoughts which surface in a threaded discussion.
When a discussion is in ThreadMode, if comments seem to be converging (to theme or strong focus), then a WikiMaster can initiate Pattern Mode by suggesting single-paragraph patterns, which capture and focus the ideas present in a threaded discussion.
Pattern Mode paragraphs are better left anonymous, or can be CollectivelySigned, so that all contributors know they are welcome to fine-tune them.
It looks like PatternMode is special case of DocumentMode
See also WikiMaster, ThreadMode