float addSteps( int stepSize, float stepHeight, int _i){

  int x = _i;// put in variable not to affect i

    int y = ( x/stepSize) % 4; // int flattens it out because the intermediar points get rounded (i/steps gives num of points between mod = 1 or =0)

float add = y*stepHeight; // increase amplitude from one

   return add;

  }

void drawStepLine(int _i){

_i = _i-1;//toget rid of point at front

float strokewidthc = 500; // how much to times vector

float strokewidthd = 10; // how much to times vector  

Vec2d a = drawLinePoints[_i];// point 1

Vec2d b = drawLinePoints[_i+1]; // point 2

  Vec2d v = b-a; // get vector minus two point vects

  Vec2d vp;

  vp.x = v.y *-1.0;// times by inverse cosine is inversly proportional to sine

  vp.y = v.x;

  vp.normalize();

  //here mess with c or d stroke point for one side

   strokewidthc =  addSteps(4,20,_i); // varies the vector size

  Vec2d c = (a+vp * strokewidthc);

  Vec2d d = (a-vp * strokewidthd);

   glVertex2f(c.x, c.y); // puts points

   glVertex2f(d.x, d.y); // puts points   

}