createCanvas(windowWidth, windowHeight);

}

​

function draw() {

  background(220, 10, 120);

  centerX = width / 2;

  centerY = height / 2;

  distX = abs(mouseX - centerX);

  distY = abs(mouseY - centerY);

​

  maxDiam = width / 2;

  diamX = maxDiam - distX;

  diamY = maxDiam - distY;

​

  fill(255);

  ellipse(mouseX, mouseY, diamX, diamY);

}

​