Singlehandedjay's post makes me think we should talk about Dee Flies. Dee flies are a little like spey flies except the wing is tied in flat on top of the hook instead of tented over the hook. Here are some pics from Pryce-Tannatt's How to Dress Salmon flies.
Here's what it looks like from the top and sides if you get it right. The wings have a scissors effect in the water. Some tyers say it helps your fly track well in the water.
The jungle cock eyes of a dee fly are tied to droop under the hook - a feature which is prob more attractive to the fish than to the tyer.
Dee flies are supposed to be tied on long shank hooks. John Farrar recommended the Partridge Low Water N. Here's an Ackroyd Dee fly tied on an extra long shank new england streamer hook.