How can I produce a celtic knot pattern in grasshopper

[laurent_delrieu]

See also this discussion

Making bridges on self intersecting curve

What about that ? I didn’t search if it was not already answered on old Grasshopper forum [image] [image] draw curve upper lower.gh (18.7 KB) [image] And it is possible to add some bridges in 3D/2D … [image] [image]