Что-то в этом роде получается
import mx.transitions.easing.*;
var steps:Number = 25;
var easy = Regular.easeInOut;
var color1:Number = 0xFFCC00;
var color2:Number = 0xFF0000;
var color3:Number = 0x000000;
var curve1 =
[
{cx:100, cy:200}, // moveTo
{cx:500, cy:200, ax:300, ay:100}, // curveTo
{cx:600, cy:800, ax:300, ay:100} // curveTo
];
var curve2 =
[
{cx:100, cy:400},
{cx:500, cy:400, ax:300, ay:500},
{cx:300, cy:100, ax:600, ay:100}
];
function(){
var c, i, s;
lineStyle(6, color1);
for(i = 0; i < curve1.length; i++){
c = curve1[i];
if(i == 0) moveTo(c.cx, c.cy);
else curveTo(c.cx, c.cy, c.ax, c.ay);
}
lineStyle(6, color2);
for(i = 0; i < curve2.length; i++){
c = curve2[i];
if(i == 0) moveTo(c.cx, c.cy);
else curveTo(c.cx, c.cy, c.ax, c.ay);
}
lineStyle(1, color3, 25);
for(s = 1; s < steps + 1; s++){
for(i = 0; i < curve1.length; i++){
var c1 = curve1[i];
var c2 = curve2[i];
var cx = easy(s, c1.cx, c2.cx - c1.cx, steps + 1);
var cy = easy(s, c1.cy, c2.cy - c1.cy, steps + 1);
var ax = easy(s, c1.ax, c2.ax - c1.ax, steps + 1);
var ay = easy(s, c1.ay, c2.ay - c1.ay, steps + 1);
if(i == 0) moveTo(cx, cy);
else curveTo(cx, cy, ax, ay)
}
}
}.call(this);