Imagine you have a stack of clear plastic sheets you know, acetate. Each sheet has a colored graphic printed on it. Now imagine that you carefully overlay one sheet on top of another to create an informational graphic that shows a step-by-step procedure. With us so far? Okay, now imagine that you're standing beside an overhead projector (remember those?) with your stack of acetates, with your palms sweating, heart pounding, anxiously waiting for your presentation to start. Phew, we don't know about you, but that brings back nerve-wracking memories of the days before PowerPoint and data projectors. Makes working with Illustrator layers so easy that it's laughable. Ha ha ha… Ha!