createCanvas(400, 400);

  colorMode(HSB);

}

​

function draw() {

  background(0);

​

  // let xinc = map(mouseY, 0, height, 1, 50);

  // xinc = constrain(xinc, 1, Infinity);

  // for (let x = 0; x < width; x += xinc) {

  //   let h = (map(x, 0, height, 0, 360) + frameCount) % 360;

  //   line(x, 0, x, height);

  // }

​

  let yinc = map(mouseX, 0, width, 1, 50);

  yinc = constrain(yinc, 1, Infinity);

  for (let y = 0; y < height; y += yinc) {

    let h = (map(y, 0, height, 0, 360) + frameCount) % 360;

    stroke(h, 255, 255);

    strokeWeight(4);

    line(0, y, width, y);

  }

}

​