Get rid of the yellow jackets marked with an X and add another neutral splice as @rmeier2 recommended on post#4. Maybe add a jacket on the line side.
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A three way switch has a total of 3 terminals, plus the ground. The graphic shows switches with 4 terminals plus ground. The center switch should be the only one with 4.
Maybe someone could google a diagram and use it as an example or maybe just sketch one out 
I was going to suggest that exact same thing a few days ago. Because I already have a few that I had saved. I knew they were a bunch out there on Google. But I didn’t want to embarrass the “artist”.
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It doesn’t need re-drawn, it just needs some tweaking.
Something that would add clarity and make it unique from other graphics on Google is if your software could twist the travelers together. It might be a regional thing, but that is how electricians around here make up the box on the rough-in.
My personal feeling is that for a report, to a non-technical person, there is no need for so much detail. In short the client not only doesn’t need, but usually doesn’t want to know how it WORKS. They want to know if it FUNCTIONS or not and its need.
An example of this with the subject at hand. The most common switching circuit is a three way at the top and bottom of the stairs or the ends of long hallways. Four way switches are less common and more likely to occur in hallways than stairs (little need to switch the lights halfway up the stairs).
The illustration would be better if it showed the application (stairway) rather than the wiring. The client doesn’t care how it’s wired, but if you show him the application he understands right away.
When someone asks you the time they don’t want to know how to build a watch!
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I definitely agree. I would never use this graphic or any of the similar ones in a report. No use at all. I thought maybe they were for courses.
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You’re probably right. In that case an actual schematic should accompany the pictorial diagram. Two single pole double throw switches and one double pole double throw switch in the middle. The pictorial diagrams show how it is wired, but NOT how it works.
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Am I the only one that noticed that the copyright is CCPIA, not InterNACHI? It’s not an image for residential home inspection clients but probably intended for advanced training purposes for commercial property inspectors.
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All the more reason to get it right.
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Exactly. It’s live but technically incorrect.
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I cannot see how this would be any more relevant in a commercial inspection. In fact, the “micro-assessment” is much less likely. (I am not saying your wrong about the possibility that is what it is for, but rather it is even less useful in a commercial application)
You may be right. Maybe it’s just about generating internet traffic with Google hits. More reason to get it right.
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The terminal issue was updated in the most recent image at the link in the OP. Thanks!
Post 13 in this thread shows the functionality using 3 and 4 way switches.
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The image is better, but still technically incorrect. Currently, there is still no neutral splice in “wall box 2” and there is still extra sheathing inside the areas that represents the wall boxes.
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What would removing the yellow jackets do to improve the image? This image is based on the image that is already located at the InterNACHI gallery only we wanted to eliminate the blue background. The creation of an image does not allow us to copy another image. We have to create them as a unique image. This is the original image that the new one was based on. We reversed the view and modernized the content. We use members on the forum to help police the image and cleanup and technical issues. We thank everyone for their help.
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How does the excess sheathing help understand how a 4-way circuit is wired?
A conductor of one pair of travelers is passing through the sheathing of a different pair of travelers. It will work on paper, but in a physical world, it would not be wired like this.
If the image doesn’t help understand how to wire a 4-way and it has nothing to do with a property inspections, what exactly is the purpose of it? Where is the 3-way switch diagram?