Explaining Visually, Or No pun at all

I write and teach courses for Learning Tree and, as a result, see a lot of courses written by other authors. I've just taken over a course that was handled by two other authors before it got to me (I suspect that the course is unwriteable, but I'll have fun trying to find a way to make it work for the participants turning up to take it). There were some very good graphics in the course but at least one complete dud which gives me a chance to talk about bad graphics.

The problem is that many (most?) writers when they think "graphics" think "picture" rather than "explaining things visually". So what happens, especially when creating a PowerPoint slide, is that the author picks some word on the page and adds a graphic that represents the word. It's not helpful--it's just a visual pun.

In this course, for instance, we talk about the enterprise service bus. So the original author (after one great graphic after another) dropped a picture of a double-decker British bus onto the slide. The next author kept the graphic, just dragging it to another place on the slide.

There's much that was wrong with this choice but the key point is that the graphic has no "explanatory value." In "Enterprise Service Bus", the metaphor being drawn on comes from an electrical bus (here, by the way, "bus" is short for "busbar"): A single item connecting multiple devices to which additional items can be plugged into; the picture implies that the metaphor is for a transport bus (here, by the way, "bus" is short for "autobus"): A large vehicle for transporting multiple people along a pre-determined route.

But this etymology is really pointless: The question is what the audience thinks/expects. My guess is that the audience doesn't make the connection between either kind of "bus." The real question is what the graphic can tell the audience. An "Enterprise Service Bus" is a software tool that supports plugging in (there's that electrical metaphor again) infinite number of software packages that can be used to process the inputs and outputs of the other plugged-in packages. Creating a graphic that builds off the electrical bus metaphor helps explain that, building off the transport bus (other than the concept of multiple passengers....somehow or other) does not.

So I took out the British bus graphic, put in a graphic of a long bar, and then added icons to the bar showing the typical kinds of packages that could be added to/accessed from an Enterprise Software bus. I needed that change: up until then, I really hadn't felt that I'd done much to improve the course that the previous two authors had passed on to me.
 
Just got back from our family's "no electronics" vacation where, as usual, I managed to get a lot of reading done. I violated the "no electronics" rule because I picked up this new course three days before I left and its due in four weeks. I'm so weak...

Reading or read

• Luck: A Novel by Joan Barfoot
• My Name Is Bosnia by Madeleine Gagnon
• The Piano Tuner: A Novel by David Mason
• The Jewish Messiah: A Novel by Arnon Grunberg
• The Adventures of Johnny Vermillion by Loren D. Estleman
• An Uncommon Enemy  by Michelle Black
• Solo Faces: A Novel by James Statler
• Out Stealing Horses: A Novel by Per Petterson 
• Song of Kali by Dan Simmons