sine  vec(u,sin(u),0) 0 6.2824
cosine  vec(u,cos(u),0) 0 6.2824
spiral  vec(sin(10*u),u,cos(10*u)) 0 30
conical-spiral vec(u*sin(10*u),u,u*cos(10*u)) 0 30 
sine-spiral vec(sin(u)*sin(10*u),u,sin(u)*cos(10*u)) 0 30