Give eye movement in Y axis

static/js/eye.js

@@ -20,12 +20,13 @@ window.onload = function () {
     window.onmousemove = function (ev) {
         const eyeOffset = body.getBoundingClientRect().x + lang.clientWidth + eye.clientWidth / 2;
         const r = (ev.clientX - eyeOffset) / (window.innerWidth - eyeOffset) / 2 + .5;
+        const ry = ev.clientY / window.innerHeight;
 
         const iX = istart + ilength * r;
         iris.setAttribute('cx', iX);
 
         const pX = iX + pstart + plength * r;
-        const pY = oY + 16 * r * (1 - r);
+        const pY = oY + 20 * r * (1 - r) * ry;
         // p(r) = y0 + a * r * (1 - r) is a parabola
         // p(0) = p(1) = y0
         // p(.5) = y0 + a / 4