The Green Machine was born on the world famous Miramichi River in New Brunswick Canada. The original version was basically some spun green deer hair and a brown hackle. Today, the fly is one of the most popular salmon flies (bugs) in New Brunswick for fishing Atlantic Salmon on the Miramichi River. Here is a look at the standard as tied by one of my favorite tyers, Marc Madore.
Here is the modern version of the Green Machine tied on tubing and utilizing super glue, UV glue and some flash. There are some great tips in here for tying well built tube flies. I would suggest using a proper mandrel rather than a needle as you can get better torque on the hair when you spin it.
Here is one more version that is worthy to note (and quite popular as well).