Lol. Make up your mind. That is not "round." That is a rectangle with rounded corners.
I guess the Tent of Meeting was also shaped like this?
What about the Ark of the Covenant? The Holy of Holies? The Temple itself?
All of these have specific dimensions defined in scripture. Width and Height by definition do not define something "round" as described in the article above.
The article is poorly written, which is not surprising given the quality of government education.
A coracle is not necessarily round:
http://www.bing.com/images/search?q=Coracles&FORM=HDRSC2
I suspect your top image is the closest one to the actual Ark seen from above. How about the fact that it’s black all round? That blew my mind. I’d always believed those drawings, etc. They’re totally off on that score.