Creating a CSS blinking eyelid effect

Question

I am trying to create a wait/countdown screen that shows an eye along with the eyelid, and eyeball with an iris effect. Given that so many of us spend time pointlessly star

Answer 1

SVG + JavaScript version

Main idea is a moving of two control points of bezier curve to forme shape of eyelid depending from delta time between animation frames:

requestAnimationFrame(draw);

function draw(t) {
  circle.setAttribute('cx', Math.sin(t/1000)*2);
  grad.setAttribute('offset', 40 + Math.sin(t/3000)*20 + '%');
  t = Math.max(0, Math.sin(t/300));
  t = (t<.5 ? 16*t*t*t*t*t : 1+16*(--t)*t*t*t*t)*6-3;
  let d = `-7 0C-2 ${t} 2 ${t} 7 0`;
  mask.setAttribute('d', `M-7 -7${d}L7 -7z`)
  eyelid.setAttribute('d', `M${d}`)
  requestAnimationFrame(draw);
}

Solution with progress and mouse move reaction

let mouse = {x:0, y:0}, 
    progress = 0;
    
setInterval(e => progress = (progress + Math.random()/100)%1, 100)
requestAnimationFrame(draw);
addEventListener('pointermove', e => {mouse.x = e.x, mouse.y = e.y})

function draw(t) {

  requestAnimationFrame(draw);
  
  // двигаем зрачок
  let dx = mouse.x - innerWidth/2,
      dy = mouse.y - innerHeight/2,
      len = Math.sqrt(dx*dx + dy*dy),
      ml = Math.min(len*10/innerHeight, 1),
      a = Math.atan2(dy, dx),
      x = Math.cos(a) * ml, 
      y = Math.sin(a)/2 * ml;
      
  circle1.setAttribute('cx', x);
  circle1.setAttribute('cy', y);
  circle2.setAttribute('cx', x);
  circle2.setAttribute('cy', y);
  
  // процент загрузки
  let r = 1.8, 
      p = progress *2 * Math.PI, 
      px = r*Math.cos(p), 
      py = r*Math.sin(p),
      arc = 1-Math.round(progress);
      
  load.setAttribute('d', `M${r},0 A${r},${r},0,${arc},0,${px},${py}L0,0z`)
  load.setAttribute('transform', `translate(${x}, ${y})`)
  
  // анимируем градиент
  let offset = Math.max(0.2, (0.5 - len/2/innerHeight))*100 + "%";  
  grad1.setAttribute('offset', offset);
  grad2.setAttribute('offset', offset);
  
  // сглаживаем время по формуле easeInOutQuint
  t = Math.max(0, Math.sin(t/300));
  t = (t<.5 ? 16*t*t*t*t*t : 1+16*(--t)*t*t*t*t)*6-3;
  
  // кривая Безье в зависимости от сглаженного значения времени
  let d = `-7 0C-2 ${t} 2 ${t} 7 0`;
  mask.setAttribute('d', `M-7 -7${d}L7 -7z`);
  eyelid.setAttribute('d', `M${d}`);
}