Guys,I'm making a Grooms Cake for my friend whom fiance is a Dallas Cowboys fan.The cake will be simple, a half sheet, the top will be a football field with the Dallas Cowys logo to include helmet ,minature football field and scoreboard with grass on one of the corners. How can I make the yardage lines straight and even. I thought of making a patttern transfer with a ruler and transferring it with piping gel after the cake is dry,then go over the pattern with a thin tip of white icing.any suggestions?

Thin rope of fondant. Use an extruder.