I made a square one just like he described to have as a trail spare.... But it worked so well I have never taken it off. The only serious drawback that I have with it is that I can't go over about 45mph in 4wd...too many vibes
You can see it in this video near the end.
http://www.edtechsupport.net/gis/millard/Cat_Canyon_Clip2.wmv
