I think they are just finishing up something they've been working on for weeks or months. So it looks like they did it in one weekend.
When I finally get into a finishing mood, I'll be posting 10-20 tops that will get done in 1 weekend. Because I have most of the square done it's just a matter of getting my behind in gear and putting them together...but I have to finish studying. So it won't be any time soon.