It rides sideways in the water presenting a single wing profile to the fish. If you get a chance take a look at Kelly Galloup's book Cripples and Spinners, he talks about the idea behind this one cam e from his observation that most spinners and cripples float in a way that the wings are together and the fly rides on its side.
Thank you Scott. I have fished this curved profile quite a lot this year from Hexes to Tricos and I can't say I have noticed any twisting of tippet or leader.
I "Michiganized" this version with the deer hair body. Kelly's are often dubbed or biot bodies. This deer hair body for an Isonychia is really a great match though in my opinion.