// settings.render=0;
import tube_js;

size(10cm,0);
currentprojection=orthographic(0,0,1);

real x(real t) {return cos(t)+2*cos(2*t);}
real y(real t) {return sin(t)-2*sin(2*t);}
real z(real t) {return 2*sin(3t);}

path3 p=scale3(4)*graph(x,y,z,0,2*pi,Spline)--cycle;
guide arc=graph(x,y,0,2*pi)--cycle;
guide cs(real s){return arc;};

draw(spacetube(p,200,100,cs,twist=0), 0.8*blue, invisible);

if(!is3D())
  shipout(bbox(0.2cm,black,RadialShade(white,paleblue)));