code: function mean( x, y ) {
  	x = abs( x );
  	y = abs( y );
  	return x + (y-x)/2.0;
  }
docs: MEAN // 
  FUNCTION: mean( x, y )
  Returns the arithmetic mean of `|x|` and `|y|`.
  
  @param {Number} x - first number
  @param {Number} y - second number
  @returns {Number} arithmetic mean