I don't know what's wrong with me, but I'm having trouble with corrugated rib. I have never done it before, and I want to use it in my next sweater project. So I have been trying samples of it. I keep messing up somehow with yarn placement. One time I even ended up with a number of yarnovers in one row! At other times I get loops like you see in two-end knitting. I'm not a beginner, but I feel like one when I try to do corrugated rib. Suggestions please.