Are you replying to me or wiggs? 
In either case, I'll spell it out for you: Working three 12-hour shifts in a seven-day workweek means that there will be four days each week during which you do not work. In other words, you DO in fact get 4 "fucking" days off per week 
Hope that clears things up, but if you have further questions I'll try my best to help you understand. God bless.
Although nurses only work 3 days per week, 12 hour shifts, there is tons of research about the negative outcomes of such shifts. It's really not that great, especially coupled with the fact that if someone dies, your license can be on the line. But, I guess that also depends if its the MD's fault.
At one point, I was working four, 10 hour days at Sears and this was perfect. Right in between 3-5 day work schedule without feeling burned out.