Machines, tools, equipment, and work aids which may be representative, but not all-inclusive, of those commonly associated with this type of work: pen, pencil, ruler, blueprints, charts, contracts, diagrams, directives, documents, forms, manuals, publications, reference books, schedules, and specifications. ESSENTIAL FUNCTIONS OF WORK (Specific assignment may include some or all of the following): Assist in the development and implementation of a developmentally appropriate preschool program for young children: Assist in planning and implementation of educational activities to meet the physical, emotional, intellectual and social.