int y = 0;

void setup() {
  size(200,200);
  background(100,100,255);
  stroke(0);
  strokeWeight(3);
  fill(0,255,255);
  drawLines();
  y = 40;
  drawLines();
}

void drawLines() {

  for (int x = 20; x < width; x+=10) {
    line(x,y,x,y+20);
  }
  save("lines.png");
}