Thank you for this further discussion. Now I understand how to deal with these vertical or horizontal lines，but I still got some problem with spiral lines, as this pic showing,
(13.9 KB) spiral problem.gh.3dm
I was wondering is there a method to restrict two line strictly from beginning to end, like from center spiral to outside gradually?
And that are pics what I want to produce as below, these are two types.
I think the algorithm is that create a spiral first then using image sampler to catch gray data to define the width of the spiral. this step two curve (outline) are produced then I use your script to generate the zigzag line between them create right pic like Monroe.
But I don’t know how to get the left pic, I only got a referent GH file the make the horizotal line image which is similar to it. Pls see the attachment.
Could you modify it to make it base on a sriral line one?
Thank you in advance!