well Jack's bday is next month. I want to make him a cake from the YT cookbook

. Im going to make him a soccer ball cake. I plan on doing the white part with cottage cheese frosting. The thing is that i dont know wat to use for the black lines?? Anybody got any ideas?? I want something healthy for them of course.
On a side note, will it be terrible if i also make them a regular duncan hines cake??? but still frost it with cottage cheese and all that.
Thanks guys