I saw someone make one of these on Eurobricks and was blown away by it.  I had never seen one before and instantly wanted to build one however I held off for a bit and worked out how it worked that week while travelling to work.  Once it got to Friday night and the wife went out, I decided to see if I could make one without using any online resources.  I also decided to make it in studdless technic beams instead of my usual studded build.

2 hours later and here it is!  Extremely happy about this especially as it did not take long to build.  I actually fancy building one a lot bigger than this.  Maybe 2-3 foot round.