Algoritme for doubling a line

[bimo]

Thanks Mike for your serious help !
with your code i got a mutch better result (picture bellow)
( and by the way i never knew that the "continue" instruction exists looks verry useful and prevent wasting time with double if conditions ! i did learn mutch from you)

i guess that would be all for this post, see you in an other soon

thanks again you've been a big help !