@Tyglik
Ok That's works very fine !
We must just play with the parameters :)
Nb of rep 321
Angle to fill 1800
Step vertical 0.125

And you obtain the Rhino Helix given my Michael here http://moi3d.com/forum/index.php?webtag=MOI&msg=277.20

Seems the same with 0.000000 deviation between the 2 Helix :)

So your method is not a "pseudo" Helix but a "real" Helix :)
Bravo for the trick! ( Ctrl + C, Erase All, Ctrl + V) that rocks!
Now we can make any Spiral or helix easily!