// RAIL-PAIR SATIN — independently authored leaf edges become one ribbon.

hoop 'round100'
fabric 'woven'
underlay 'auto'
density 0.42
lock 0.6

// A Bézier curve returns a path; these two paths are the ribbon's rails.
let leafBase = [0, -20]  // [xy: disc 24]
let leafTip = [0, 22]    // [xy: disc 24]
let edgeLeft = bezier(leafBase, [-3.5, -10], [-3, 14], leafTip, 1.2)
let edgeRight = bezier(leafBase, [3.5, -10], [3, 14], leafTip, 1.2)

color 0
// `satinbetween` pairs matching distances along the two rails automatically.
satinbetween(edgeLeft, edgeRight)
trim

// railspine shares satinbetween's exact arc-length pairing.
let vein = railspine(edgeLeft, edgeRight)
color 1
up setpos(vein[0]) down
stitchlen 2
sewpath(vein)
trim