Well, I tried. I think it's something that takes a lot of energy, stamina, and practice. Here are some tips and steps to attempt this cake. I think I'll be trying again when it hasn't been a long, exhausting day at work and it's earlier than 11:30 at night. :o)
When you put icing into a decorating bag (or ziploc with the corner snipped off), fold the bag over itself about halfway. This helps you have room to get the icing all the way to the tip of the bag and also keeps your hand clean.
I use a cake spatula to put the icing into the bag (you could also use a butterknife). With the bag folded over like this, you can use your fingers to pinch the spatula at the top to slide the icing off and into the bag.
Use a serated knife to cut off the "hump" left from baking. It will make your cake level when stacked and also gives you something to snack on while you decorate.
It doesn't matter if they're the same height, as long as both cakes are relatively even. choose the cake that has the smoother "bottom" surface to serve as the top of your stacked caked.
Place the other cake crumb side down on top of your filling.
When you ice a cake, start at the top with a HUGE glob, ice from the center out to the sides and push it over the edge.
I used a small round bowl I had to indent a circle in the center of my cake so that I could make sure my stripes were evenly sized.
Now that I have a guide line, I can begin decorating. The indentation will be covered with icing later.
Using my stiff icing, I tried to make even stripes around. I tried to do all one color, but soon realized it's easier to just switch bags while decorating, start on one side, and work your way around. Now I know for next time.
I wanted to do more stripes than this, but since I put orange on first, didn't have room. Also, it was about 12:30 and I was tired. :o)
I added a shell border to the bottom and piped stars on the top of the stripes to cover my uneven and messy ends.
Using a small tip, I piped the lettering in the middle of the circle I left on top.