let g = 200;

let b = 250;

​

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(255);

  fill(r, g, b);

  textSize(mouseX+mouseY);

  text("a", 150, 150 + 99);

  noFill();

  //noStroke();

  rect(150, 150, 100, 100);

  if (mouseX >= 150 && mouseX <= 150 + 100 && mouseY >= 150 && mouseY <= 150 +100) {

    //if we've rolled over do something

    r = 400

    g = 200

    b = 250

  } else {

    r=0

    g=0

    b=0

  }

}