Readability is primarily the concern of designer
It is the intended result of the complete process of presentation of textual material in order to communicate meaning.
Visual aids: a tool of persuasion
Projection equipment: slide projectors, presentations, overhead projectors, and computer projectors.
Book design is the art of incorporating the content, style, format, design, and sequence of the various components of a book into a coherent whole. In the words of Jan Tschichold, book design, "methods and rules upon which it is impossible to improve, have been developed over centuries. To produce perfect books, these rules have to be brought back to life and applied."
Visual aids are often used to help audiences of informative and persuasive speeches understand the topic being presented. Visual aids can play a large role in how the audience understands and takes in information that is presented. There are many different types of visual aids that range from handouts to presenataions. The type of visual aid a speaker uses depends on their preference and the information they are trying to present.

Each type of visual aid has pros and cons that must be evaluated to ensure it will be beneficial to the overall presentation. Before incorporating visual aids into speeches, the speaker should understand that if used incorrectly, the visual will not be an aid, but a distraction.