color lc = color(0, 0, 0);
color pc = color(255, 0, 0);
float pr = 6.0;

// draw the list of points in array c connected with lines
void drawCurve(ArrayList c, boolean withPoints) {
  PVector p0, p1;
  p0 = (PVector) c.get(0);
  if (withPoints) {
    stroke(pc);
    ellipse(p0.x, p0.y, pr, pr);
  }
  for(int i=1; i < c.size(); i++) {
    p1 = (PVector) c.get(i);
    stroke(lc);
    line(p0.x, p0.y, p1.x, p1.y);
    if (withPoints) {
      stroke(pc);
      ellipse(p1.x, p1.y, pr, pr);
    }
    p0 = p1;
  }
}