NB. helix
NB.
NB. the y-axis is vertical
NB. press the Y key to rotate.

helix=: 3 : 0
u=. steps 0,(o. +:y.), 20
v=. steps _1 1 20
x=. (cos u) */ v
y=. u +/ v * 0
z=. (sin u) */ v
1.25*makexyz fit11 each x;y;z
)

COLOR=: ORCHID
CLEARCOLOR=: IVORY

demo=: 3 : 0
stdlistlight''
2 drawsurface makenewlist helix 1.5
)
