import processing.pdf.*;
PGraphics pg;
int canvaposition = 0;

void setup() {
  size(530, 750, PDF, "singleFrameWave.pdf");

  background(10);
  pg = createGraphics(40, 40);
  drawincanva();

  while (canvaposition < height) {
    drawincanva();
  }
}

void draw() {

}

void drawincanva(){
   canvaposition+=random(1, 10);;
    pg.beginDraw();
    pg.background(100);
    pg.stroke(255);
    pg.line(20, 20, canvaposition, canvaposition);
    pg.endDraw();
    image(pg, 9, 30); 
    image(pg, 51, 30);
}