Open your article and stuck on the words:
The fillet using the border-radius property described in CSS3, but only recently more or less embedded in the browser ... for IE, the problem of rounding is solved by uploading the plugin using css PIE.htc (behavior: url(PIE.htc);)
Long could not understand - it is trolling like this? Then I figured it out - the article is at least from 2011.
If you returned to the present at once would remember about the radial gradient and clip-path.