// width: 893px; height: 50px
int num = 20;
float[] dx = new float[num];
float[] dy = new float[num];

void setup() {
  size(893, 50);
  for (int i = 0; i < num; i++) {
    dx[i] = i * 5;
    dy[i] = 12 + (i * 6);
  }
}

void draw() {
  background(204);
  for (int i = 0; i < num; i++) {
    dx[i] = dx[i] + 0.5;
    if (dx[i] > 893) {
      dx[i] = -100;
    }
    diagonals(dx[i], dy[i]);
  }
}

void diagonals(float x, float y) {
  smooth();
  float r = mouseX;
  float s = mouseY;
  line(x, y, r+10, s-10);
  line(x+10, y, r+20, s-20);
  line(x+20, y, r+30, s-30);
}