Created a login form with an SVG avatar that responds to the input in the email field. Used the GSAP TweenMax library + GSAP's MorphSVG plugin for the animating.
Email validation is very simple and crude just for the purposes of getting this prototype working.
FWIW: I (@rondy) am not the creator of the content shared here, which is an excerpt from Edmond Lau's book. I simply copied and pasted it from another location and saved it as a personal note, before it gained popularity on news.ycombinator.com. Unfortunately, I cannot recall the exact origin of the original source, nor was I able to find the author's name, so I am can't provide the appropriate credits.