Thanks all for looking into this. Sorry, I forgot to mention the environment stuff...:
Windows 10
Chrome Version 61.0.3163.100 (Official Build) (64-bit)
CPU: Intel i5-4690
Video Card: HIS R9 280 IceQ OC 3GB GDDR5 (i.e. AMD Radeon R9 200 Series)
I'm running 3 monitors, 1 of them set to 1024x768 where I see the issues.
I have, just now, tested on a few different machines. My other Windows 10 machine (a 5 year old high end Asus laptop) shows the artifacts, but less so then my development machine. This laptop *is* the machine I will run the presentation from at the convention, so that's my target environment. My Mac's (2 different MBP's) do not show the lines at all (ya Mac!). I won't have access to a projector until a few days before the presentation. So, I don't know if this will be visible or not. If there is not an obvious software/coding solution, I guess my next best step would be to find a projector and see if this is really going to be an issue or not.
I've attached an image of what I see. I had to remove colors and reduce the quality of the image quite a bit to fit the image upload size restrictions so ignore the swirls and just note the vertical lines in the background image.
Thanks a bunch!
Darrin