int    NUM = 10, WEIGHT = 0;
float  D   = 0.0;

void setup()
{
  size(600, 600);
  frameRate(60);
  smooth();
  noFill();
  colorMode(HSB);
  stroke(255);
  background(0);
}

void keyPressed()
{
  if (key >= '0' && key <= '9')
    WEIGHT = int("" + key);
}

void draw()
{
  noStroke();
  fill(0, 0, 0, 5);
  rect(0, 0, width, height);
  if (0 == WEIGHT)
    strokeWeight((frameCount % 30) < 20 ? 1 : 5);
  else
    strokeWeight(WEIGHT);
  noFill();
  stroke(frameCount % 255, 127, 255, 150);
  D += 0.001;
  beginShape();
  curveVertex(0, frameCount % height);
  for (int x = 0; x < width; x += width / NUM)
  {
    float  y = (0.5 - noise((PI + x + frameCount * 0.1) * 0.01 * D)) * height / 2;
    curveVertex(x, y + (frameCount % height));
  }
  curveVertex(width, frameCount % height);
  curveVertex(width, frameCount % height);
  endShape();
}