Instructional Graphics  The purpose of most instructional
graphics is to help explain something to the viewer in a manner
that hopefully increases retention of the subject matter.
Instructional graphics have seven possible functions:    1.
Descriptive - To show what an object looks like.   2. Expressive
- To make an impact on the learner.   3. Constructional - To
show how the parts fit together into the whole.   4. Functional
- To show a process or the organization of a system in a
simplified manner.   5. Logico-mathematical - To display a
mathematical concept such as a curve graph. Some line graphs and
charts with a scaled X and Y axis fall into this category.   6.
Algorithmic - To show a holistic picture of the range of
possibilities. Flow charts fall into this category.   7. Data
display - Illustrating textual data visually. Bar charts, pie
charts, and histograms fall into this category.
Representational, Analogical, or Arbitrary  Instructional
graphics can also be classified as representational, analogic