code: function calculateNewBorderRadius( match, pre ) {
  		var values,
  			args = [].slice.call( arguments ),
  			firstGroup = args.slice( 2, 6 ).filter( function ( val ) { return val; } ),
  			secondGroup = args.slice( 6, 10 ).filter( function ( val ) { return val; } ),
  			post = args[ 10 ] || '';
  
  		if ( secondGroup.length ) {
  			values = flipBorderRadiusValues( firstGroup ) + ' / ' + flipBorderRadiusValues( secondGroup );
  		} else {
  			values = flipBorderRadiusValues( firstGroup );
  		}
  
  		return pre + values + post;
  	}
docs: Invert a set of border radius values.
  
  @private
  @param {string} match Matched property
  @param {string} pre Text before value
  @param {string} [firstGroup1]
  @param {string} [firstGroup2]
  @param {string} [firstGroup3]
  @param {string} [firstGroup4]
  @param {string} [secondGroup1]
  @param {string} [secondGroup2]
  @param {string} [secondGroup3]
  @param {string} [secondGroup4]
  @param {string} [post] Text after value
  @return {string} Inverted property