module polygonangles(points) // TODO: paths?
{
  polygon(points);
  for(p=[0:len(points)-1])
  {
    a=points[(p+1)%len(points)];
    b=points[(p+len(points)-1)%len(points)];
    c=points[p];
    adeg=atan2(a[0]-c[0], a[1]-c[1]);
    bdeg=atan2(b[0]-c[0], b[1]-c[1]);
    deg=min((bdeg-adeg+360)%360, (adeg-bdeg+360)%360);
    translate(c)color("#000000")text(str(deg), size=1);
  }
}

// Example:
polygonangles([[0,0],[-1,5],[10,12],[10,0]]);