I believe that Omar posted on the multimedia principles that he has experienced in his educational life. He discussed the principle of coherence and spatial contiguity. He said that he has sat through many presentations that were confusing because the presenter failed to remove extraneous material (coherence principle), and/or the images and corresponding textual explanations were far apart that they seemed unrelated (spatial contiguity). Even though Omar explains the two principles thoroughly, he fails to show the importance of the many other multimedia principles.