Higher complexity, sometimes introduced by the use of texture, increased detail, or three-dimensional shading, enhances the figural quality of an element. Elements that have incomplete outlines, as if fading at the edges, will be perceived as ground. All details that might have been included on the ground or in the background sky have been ignored in this otherwise realistic diagram. Other than the shadow on the ground, the storm cloud itself is the only element that is drawn in three dimensions. Interaction with the illustration is encouraged through the use of captions or questions and references in the text.
Learners tend to avoid redundancy.
Consequently, illustrations should always be referred to within the lecture or text to encourage attention and to point out the pertinent information. Instructors should never assume that students will study illustrations just because they are there. Asking questions about an illustration is the surest way to get students to interact with it. If questions are used, they should cover all the important information presented. Pictorial elements and words complement each other.