Es3

function setup() {

  createCanvas(windowWidth, windowHeight);

}

​

// Global

var nRows = 75;

​

function draw() {

  background(100);

  for(var i = 0; i <= nRows; i++) {

    //top

    stroke(map(mouseX, 0, width, 0, 255), map(i*10, 0, width, 0, 255), 70);

    line(width/nRows*i, 0, mouseX, mouseY);

    //bottom

    stroke(map(mouseY, 0, width, 0, 255), map(i*10, 0, width, 0, 255), 100);

    line(width/nRows*i, height, mouseX, mouseY);

  }

}