CSS Shapes allows one to specify a geometric "shape-outside" for a float. Content will wrap around the float's shape-outside, instead of its rectangular boundary. The shape-outside property can be specified with a geometric primitive, like an ellipse or a polygon, or by the pixels of an image's alpha channel whose values are greater than shape-image-threshold. A shape-outside's boundary can be uniformly expanded with the shape-margin property.
Docs: http://blogs.adobe.com/webplatform/category/features/css-shapes/ http://www.html5rocks.com/en/tutorials/shapes/getting-started/ https://developer.mozilla.org/en-US/docs/Web/CSS/shape
Samples: https://github.com/GoogleChrome/samples/tree/gh-pages/css-shapes