Rotation & background experiment
Move your mouse around, see the result. No SVG/canvas/anything else! I really like the effect
More rotational objects can be added easily, just add the appropriate HTML structure (including the necessary classes)
This could also be combined with a CSS-only square container and made responsive very easily. For an example of the technique, check here http://codepen.io/Zeaklous/pen/ImGaH
Inspired by http://25.media.tumblr.com/918162ed1f057a800b05dca55cf30764/tumblrmuihqpB1Kx1rf78nfo1r1_400.gif
All gifs taken from http://seamlessgifs.tumblr.com/