This is a cake that I made for a barbeque on Memorial Day Weekend.
I doubled my standard white cake recipe, and poured it onto two cookie sheets, to make a traditional sheet cake. It's frosted and filled with homemade cream cheese frosting, and decorated with blueberries and raspberries.
Using the left over frosting, I piped stars in between the raspberry stripes. To make sure that I had 7 red stripes and 6 white stripes, I measured the width of the cake and divided by 13. Then I made 13 marks with a toothpick and added the "stars and stripes".