A schema filled in with default values is called a prototype . Whereas a schema is an organized abstract framework of objects and relations, a prototype consists of a specified set of expectations. One function of schemas is to relate terms drawn different linguistic domains. For example, the writing schema relates pencils, pens, chalk, typewriters, etc., to paper, blackboards, newspapers, manuscripts, etc., to English, French, Arabic, etc., to authors, correspondents, pen-pals, memos, etc. Or, to put it another way, schemas can be hierarchically structured.
Some schemas are especially fundamental and fertile.
The body is a container. Lakoff's well-known book Women, Fire, and Dangerous Things discusses these kinds of things. Languages often have terms which identify ways in which the full schema fails or is only partially satisfactory. The term scrawl refers to a failure to make one's writing on something fully legible, the term illiterate refers to someone who is not able to utilize the writing schema because they cannot read or write effectively. Such terms can only be defined and understood through a comprehension of the full schema and what can go wrong within it.