The boundaries of what's possible are changing. It's no longer necessary to corral text into rectangular parcels. When the CSS Exclusions feature has been fully implemented, inline content can spread out into any shape you can define with rectangles, polygons, ellipses, circles, even SVG paths. What you're seeing here demonstrates the initial WebKit support for certain kinds of polygons. You can read more about that here. We're not in Kansas anymore, Toto.