Right, well stated [MENTION=129606]Knight-Errant[/MENTION], and you had me convinced for a minute that the way it is set up now is accurate. But in thinking further about your rev counter analysis, and the fan comparison, you have identified the crux of the issue. When you are looking for the proper intermittent wiper speed, you are not primarily concerned with the speed of the wipers per se, you are concerned with the amount of time between swipes. In fact the actual time it takes for the wipers to cross the windshield each time they are activated is the same each time. So, unlike rev counters, the primary purpose of the intermittent wiper graph is not to represent speed, it is to represent time! In other words, with intermittent wipers, a clock that shows a time that gets larger as the time between wiper swipes increases is the best way of telling you the information you want to know. Specifically, assume for example you are dealing with a very light mist, and you want a long period of time between wiper swipes. So, you look down at your intermittent wiper dial, and what do you want that graphic to tell you? You want it to tell you, which setting is going to give me the longest period of time between wiper swipes? It is counter-intuitive under these circumstances to choose the smallest part of the graph!
I understand what you're saying but people mostly think "i need more wipes to occur over a period of time" or " I need fewer wipes to occur over a period of time" and that syncs up with how most things are commonly measured quantity/time, occurrence/time, distance/time. Since engineers (not philosophers or English majors) design car components, and since the way people think is, by in large, in line with the way the engineers think, you have the image that is on the stalk.
People usually don't think "I need less time to occur between wipes" rather they think "I want a higher volume of wipes." It is the same "concept or idea", just expressed and viewed differently, but as I mentioned for most intents and purposes things are measures in X/time. People want their wipers to be "faster" but this is, in a sense, a sloppy or imprecise use of language since they just want more wipes (or less time between wipes), they don't actually want the speed of the wiper across the windshield to increase.
You're reasoning isn't "wrong", it is just unconventional in the realm that we're examining and how people generally think....you're marching to a different your own drum is what I'm saying (and that's ok, but it means you're going to be frustrated by the image). The image doesn't have to make sense to all people, it just has to make sense to the majority of people. The average person is going to think "more wipes" when the image on the stalk is thick, instead of "more time between wipes."
Basically your struggle is between the use of language (the definition of "intermittent) and how technical individuals (and most of the public) measure things and then convert that measurement to an easily discernible image that will represent the concept. "Intermittent" is defined as "marked by intervals of complete quietude occurring between two periods of activity", and you believe the image should chart the "interval of quietude". Even though there is indeed a period of "quietude", most people are concerned with "the number of wipes occurring" and we tend to measure things as the number of "Xs" over a period of time, and this contradiction is what you're disagreeing with.
On the most basic level, the image has to "make sense" to a person who isn't familiar with the term "intermittent wiper". Most people are going to think "more wipes" or "faster" with they see the thick line. They have to figure out what the image means without knowing the name. If you see "ATRAC" on a button in a 4runner for the first time, you have no idea what the means without reading the manual, but you know "red" is hot and "blue" is cold for temperature controls, "thin" means less "thick" means more, a window image lets you know the button operates the power windows, etc. The "thick=more time between wipes" concept is a bit abstract and not intuitive. Intuitive is what car interior designers strive for (although they are not always successful).
As an aside, the time the wiper takes to complete a wipe can be varied (or does vary depending on the setting) for certain car models (i'm speaking of the the speed of the wiper blade as it goes across the windshield, or the speed to complete a wipe cycle rather than the speed between wipe cycles)...further complicating the analysis.