code: private void buildFaceArgs(final List<String> args) {
  		if (mode != null && CowFace.isKnownMode(mode)) {
  			args.add(flagify(mode));
  		} else {
  			if (eyes != null) {
  				args.add(flagify(CowsayCli.Opt.EYES.toString()));
  				args.add(eyes);
  			}
  			if (tongue != null) {
  				args.add(flagify(CowsayCli.Opt.TONGUE.toString()));
  				args.add(tongue);
  			}
  			if (cowfile != null) {
  				args.add(flagify(CowsayCli.Opt.COWFILE.toString()));
  				args.add(cowfile);
  			}
  		}
  	}
docs: Face specific flags, either a face mode or face customizations.
  @param args The arg line to add to.