Wow, I think you would need to make a LOT of circles to have these babies pay off... very pricey in my opinion....
I haven't heard of it either. But, after watching the video, I'm sure I'd burn my finger tips in the process. While the concept is nice, I think it is more time consuming than other methods.
I was too curious not to find out how these are used
Go to link and scroll half way down to see video.
No I haven't. Are they used to make yoyos are circles for dresdens?